Feedstock lines for additive manufacturing of an object, and systems and methods for creating feedstock lines

ABSTRACT

A feedstock line (100) comprises elongate filaments (104), a resin (124), and optical direction modifiers (123). The resin (124) covers the elongate filaments (104). The optical direction modifiers (123) are covered by the resin (124) and are interspersed among the elongate filaments (104). Each of the optical direction modifiers (123) has an outer surface (184). Each of the optical direction modifiers (123) is configured such that when electromagnetic radiation (118) strikes the outer surface (184) from a first direction, at least a portion of the electromagnetic radiation (118) departs the outer surface (184) in a second direction that is at an angle to the first direction to irradiate, in the interior volume of the feedstock line (100), the resin (124) that, due at least in part to the elongate filaments (104), is not directly accessible to the electromagnetic radiation (118), incident on the exterior surface of the feedstock line.

FIELD

The present disclosure relates to additive manufacturing.

BACKGROUND

A 3D printing process may use a feedstock material, extruded from aprint head, to additively manufacture a part by layering the feedstockmaterial. The feedstock material may comprise a polymer and reinforcingfibers, such as carbon fibers, which are opaque to visible andultra-violet light. When the polymer in the feedstock material is aphotopolymer, a source of curing energy may be directed at the feedstockmaterial, dispensed by the print head, to solidify the feedstockmaterial. However, when the reinforcing fibers are opaque to the curingenergy, they cast shadows and prevent the curing energy, originatingdirectly from the source of curing energy, from irradiating and curingthe photopolymer in the shadows.

SUMMARY

Accordingly, apparatuses and methods, intended to address at least theabove-identified concerns, would find utility.

The following is a non-exhaustive list of examples, which may or may notbe claimed, of the subject matter according to the invention.

One example of the subject matter according to the invention relates toa feedstock line for additive manufacturing of an object. The feedstockline has a feedstock-line length and an exterior surface, defining aninterior volume of the feedstock line. The feedstock line compriseselongate filaments, a resin, and optical direction modifiers. Theelongate filaments extend along at least a portion of the feedstock-linelength. The resin covers the elongate filaments. The optical directionmodifiers each extend along only a portion of the feedstock-line length.The optical direction modifiers are covered by the resin and areinterspersed among the elongate filaments. Each of the optical directionmodifiers has an outer surface. Each of the optical direction modifiersis configured such that when electromagnetic radiation strikes the outersurface from a first direction, at least a portion of theelectromagnetic radiation departs the outer surface in a seconddirection that is at an angle to the first direction to irradiate, inthe interior volume of the feedstock line, the resin that, due at leastin part to the elongate filaments, is not directly accessible to theelectromagnetic radiation, incident on the exterior surface of thefeedstock line.

Inclusion of optical direction modifiers in the feedstock linefacilitates penetration of the electromagnetic radiation into theinterior volume of the feedstock line for irradiation of the resin,despite regions of the resin being in the shadows of the elongatefilaments cast by the direct (i.e., line-of-sight) application of theelectromagnetic radiation. In other words, even when the electromagneticradiation is shielded from directly reaching all regions of the resin,the optical direction modifiers will redirect the electromagneticradiation to disperse or scatter the electromagnetic radiation toindirectly reach regions of the resin. As a result, the feedstock linemay be more easily cured with the electromagnetic radiation, may be moreevenly cured with the electromagnetic radiation, may be more thoroughlycured with the electromagnetic radiation, and/or may be more quicklycured with the electromagnetic radiation. This configuration offeedstock line is particularly well suited for additive manufacturing ofthe fused filament fabrication variety, in which the feedstock line isdispensed by a print head, or nozzle, and a source of curing energy(e.g., electromagnetic radiation) directs the curing energy at thefeedstock line as it is being dispensed to cure the resin in situ.

Another example of the subject matter according to the invention relatesto a system for creating a feedstock line for additive manufacturing ofan object. The feedstock line has a feedstock-line length. The systemcomprises a prepreg-tow supply, a prepreg-tow separator, anoptical-direction-modifier supply, a combiner, and at least one heater.The prepreg-tow supply is configured to dispense a precursor prepregtow, comprising elongate filaments and resin, covering the elongatefilaments. The prepreg-tow separator is configured to separate theprecursor prepreg tow, dispensed from the prepreg-tow supply, intoindividual ones of the elongate filaments, at least partially coveredwith the resin, or into subsets of the elongate filaments, at leastpartially covered with the resin. Each of the subsets comprises aplurality of the elongate filaments. The optical-direction-modifiersupply is configured to dispense optical direction modifiers to beapplied to the individual ones of the elongate filaments, at leastpartially covered with the resin, or the subsets of the elongatefilaments, at least partially covered by the resin, originating from theprepreg-tow separator. Each of the optical direction modifiers has anouter surface, and each of the optical direction modifiers is configuredsuch that when electromagnetic radiation strikes the outer surface froma first direction, at least a portion of the electromagnetic radiationdeparts the outer surface in a second direction that is at an angle tothe first direction. The combiner is configured to combine theindividual ones of the elongate filaments, at least partially coveredwith the resin, and the optical direction modifiers, dispensed by theoptical-direction-modifier supply, or to combine the subsets of theelongate filaments, at least partially covered with the resin, and theoptical direction modifiers, dispensed by the optical-direction-modifiersupply, into a derivative prepreg tow so that the optical directionmodifiers are interspersed among the elongate filaments. At least theone heater is configured to heat at least one of (i) the resin in theprecursor prepreg tow, dispensed from the prepreg-tow supply, to a firstthreshold temperature to facilitate separation of the precursor prepregtow by the prepreg-tow separator into the individual ones of theelongate filaments or into the subsets of the elongate filaments; (ii)the resin that at least partially covers the individual ones of theelongate filaments or the subsets of the elongate filaments, originatingfrom the prepreg-tow separator, to a second threshold temperature tocause wet-out of the optical direction modifiers and the elongatefilaments in the derivative prepreg tow by the resin; or (iii) the resinthat at least partially covers the elongate filaments in the derivativeprepreg tow, originating from the combiner, to a third thresholdtemperature to cause wet-out of the optical direction modifiers and theelongate filaments in the derivative prepreg tow by the resin.

Creating the feedstock line from the precursor prepreg tow permits theuse of off-the-shelf prepreg reinforcement fiber tows. The prepreg-towseparator separates the precursor prepreg tow into the individual onesof the elongate filaments that are at least partially covered with theresin or into the subsets of the elongate filaments that are at leastpartially covered with the resin, so that the optical directionmodifiers may be operatively interspersed with the elongate filaments.The combiner then combines the elongate filaments and the opticaldirection modifiers, together with the resin, into the derivativeprepreg tow to ultimately become the feedstock line. At least the oneheater heats the resin to facilitate one or both of separation of theprecursor prepreg tow or wetting-out of the elongate filaments and theoptical direction modifiers in the derivative prepreg tow.

Yet another example of the subject matter according to the inventionrelates to a method of creating a feedstock line for additivemanufacturing of an object. The feedstock line has a feedstock-linelength. The method comprises separating a precursor prepreg tow,comprising elongate filaments and resin, covering the elongatefilaments, into individual ones of the elongate filaments, at leastpartially covered with the resin, or into subsets of the elongatefilaments, at least partially covered with the resin. Each of thesubsets comprises a plurality of the elongate filaments. The method alsocomprises applying optical direction modifiers to the individual ones ofthe elongate filaments, at least partially covered with the resin, orthe subsets of the elongate filaments, at least partially covered withthe resin.

Each of the optical direction modifiers has an outer surface, and eachof the optical direction modifiers is configured such that whenelectromagnetic radiation strikes the outer surface from a firstdirection, at least a portion of the electromagnetic radiation departsthe outer surface in a second direction that is at an angle to the firstdirection. The method further comprises combining the optical directionmodifiers with the individual ones of the elongate filaments, at leastpartially covered with the resin, or the subsets of the elongatefilaments, at least partially covered with the resin, into a derivativeprepreg tow so that the optical direction modifiers are interspersedamong the elongate filaments. The method additionally comprises heatingat least one of (i) the resin in the precursor prepreg tow prior toseparating the precursor prepreg tow into the individual ones of theelongate filaments, at least partially covered with the resin, or intothe subsets of the elongate filaments, at least partially covered withthe resin, to a first threshold temperature to facilitate separating theprecursor prepreg tow; (ii) the resin, at least partially covering theindividual ones of the elongate filaments or the subsets of the elongatefilaments following separating the precursor prepreg tow into theindividual ones of the elongate filaments, at least partially coveredwith the resin, or into the subsets of the elongate filaments, at leastpartially covered with the resin, and prior to combining the opticaldirection modifiers and the individual ones of the elongate filaments,at least partially covered with the resin, or the subsets of theelongate filaments, at least partially covered with the resin, to asecond threshold temperature to cause wet-out of the optical directionmodifiers and the elongate filaments in the derivative prepreg tow bythe resin; or (iii) the resin, at least partially covering the elongatefilaments in the derivative prepreg tow, to a third thresholdtemperature to cause wet-out of the optical direction modifiers and theelongate filaments in the derivative prepreg tow by the resin.

Creating the feedstock line from the precursor prepreg tow permits theuse of off-the-shelf prepreg reinforcement fiber tows. Separating theprecursor prepreg tow into the individual ones of the elongate filamentsthat are at least partially covered with the resin or into the subsetsof the elongate filaments that are at least partially covered with theresin enables the optical direction modifiers to be operativelyinterspersed among and combined with the elongate filaments. Heating theresin facilitates one or both of separation of the precursor prepreg towor wetting-out of the elongate filaments and the optical directionmodifiers in the derivative prepreg tow.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described one or more examples of the invention in generalterms, reference will now be made to the accompanying drawings, whichare not necessarily drawn to scale, and wherein like referencecharacters designate the same or similar parts throughout the severalviews, and wherein:

FIG. 1 is a block diagram, schematically representing a feedstock linefor additive manufacturing of an object, according to one or moreexamples of the present disclosure;

FIG. 2 is a block diagram, schematically representing a system forcreating a feedstock line for additive manufacturing of an object,according to one or more examples of the present disclosure;

FIG. 3 is a block diagram, schematically representing an opticalwaveguide, according to one or more examples of the present disclosure;

FIG. 4 is a schematic representation of a feedstock line of FIG. 1,according to one or more examples of the present disclosure;

FIG. 5 is a schematic representation of a feedstock line of FIG. 1,according to one or more examples of the present disclosure;

FIG. 6 is a schematic representation of a feedstock line of FIG. 1,according to one or more examples of the present disclosure;

FIG. 7 is a schematic representation of a feedstock line of FIG. 1,according to one or more examples of the present disclosure;

FIG. 8 is a schematic representation of an optical fiber that may bemodified to create an optical waveguide of FIG. 3, according to one ormore examples of the present disclosure;

FIG. 9 is a schematic representation of an optical waveguide, accordingto one or more examples of the present disclosure;

FIG. 10 is a schematic representation of an optical waveguide, accordingto one or more examples of the present disclosure;

FIG. 11 is a schematic representation of an optical waveguide, accordingto one or more examples of the present disclosure;

FIG. 12 is a schematic representation of an optical waveguide, accordingto one or more examples of the present disclosure;

FIG. 13 is a schematic representation of a system of FIG. 2, accordingto one or more examples of the present disclosure;

FIG. 14 is a schematic representation of a system of FIG. 2, accordingto one or more examples of the present disclosure;

FIG. 15 is a schematic representation of an optical direction-modifyingparticle, according to one or more examples of the present disclosure;

FIG. 16 is a schematic representation of an optical direction-modifyingparticle, according to one or more examples of the present disclosure;

FIG. 17 is a schematic representation of an optical direction-modifyingparticle, according to one or more examples of the present disclosure;

FIGS. 18A and 18B collectively are a block diagram of a method ofcreating a feedstock line for additive manufacturing of an object,according to one or more examples of the present disclosure;

FIG. 19 is a block diagram of a method of modifying an optical fiber tocreate an optical waveguide, according to one or more examples of thepresent disclosure;

FIG. 20 is a block diagram of a method of modifying an optical fiber tocreate an optical waveguide, according to one or more examples of thepresent disclosure;

FIG. 21 is a block diagram of a method of modifying an optical fiber tocreate an optical waveguide, according to one or more examples of thepresent disclosure;

FIG. 22 is a block diagram of aircraft production and servicemethodology; and

FIG. 23 is a schematic illustration of an aircraft.

DESCRIPTION

In FIGS. 1-3, referred to above, solid lines, if any, connecting variouselements and/or components may represent mechanical, electrical, fluid,optical, electromagnetic and other couplings and/or combinationsthereof. As used herein, “coupled” means associated directly as well asindirectly. For example, a member A may be directly associated with amember B, or may be indirectly associated therewith, e.g., via anothermember C. It will be understood that not all relationships among thevarious disclosed elements are necessarily represented. Accordingly,couplings other than those depicted in the block diagrams may alsoexist. Dashed lines, if any, connecting blocks designating the variouselements and/or components represent couplings similar in function andpurpose to those represented by solid lines; however, couplingsrepresented by the dashed lines may either be selectively provided ormay relate to alternative examples of the present disclosure. Likewise,elements and/or components, if any, represented with dashed lines,indicate alternative examples of the present disclosure. One or moreelements shown in solid and/or dashed lines may be omitted from aparticular example without departing from the scope of the presentdisclosure. Environmental elements, if any, are represented with dottedlines. Virtual imaginary elements may also be shown for clarity. Thoseskilled in the art will appreciate that some of the features illustratedin FIGS. 1-3 may be combined in various ways without the need to includeother features described in FIGS. 1-3, other drawing figures, and/or theaccompanying disclosure, even though such combination or combinationsare not explicitly illustrated herein. Similarly, additional featuresnot limited to the examples presented, may be combined with some or allof the features shown and described herein.

In FIGS. 18-22, referred to above, the blocks may represent operationsand/or portions thereof, and lines connecting the various blocks do notimply any particular order or dependency of the operations or portionsthereof. Blocks represented by dashed lines indicate alternativeoperations and/or portions thereof. Dashed lines, if any, connecting thevarious blocks represent alternative dependencies of the operations orportions thereof. It will be understood that not all dependencies amongthe various disclosed operations are necessarily represented. FIGS.18-22 and the accompanying disclosure describing the operations of themethods set forth herein should not be interpreted as necessarilydetermining a sequence in which the operations are to be performed.Rather, although one illustrative order is indicated, it is to beunderstood that the sequence of the operations may be modified whenappropriate. Accordingly, certain operations may be performed in adifferent order or simultaneously. Additionally, those skilled in theart will appreciate that not all operations described need be performed.

In the following description, numerous specific details are set forth toprovide a thorough understanding of the disclosed concepts, which may bepracticed without some or all of these particulars. In other instances,details of known devices and/or processes have been omitted to avoidunnecessarily obscuring the disclosure. While some concepts will bedescribed in conjunction with specific examples, it will be understoodthat these examples are not intended to be limiting.

Unless otherwise indicated, the terms “first,” “second,” etc. are usedherein merely as labels, and are not intended to impose ordinal,positional, or hierarchical requirements on the items to which theseterms refer. Moreover, reference to, e.g., a “second” item does notrequire or preclude the existence of, e.g., a “first” or lower-numbereditem, and/or, e.g., a “third” or higher-numbered item. Reference hereinto “one example” means that one or more feature, structure, orcharacteristic described in connection with the example is included inat least one implementation. The phrase “one example” in various placesin the specification may or may not be referring to the same example.

As used herein, a system, apparatus, structure, article, element,component, or hardware “configured to” perform a specified function isindeed capable of performing the specified function without anyalteration, rather than merely having potential to perform the specifiedfunction after further modification. In other words, the system,apparatus, structure, article, element, component, or hardware“configured to” perform a specified function is specifically selected,created, implemented, utilized, programmed, and/or designed for thepurpose of performing the specified function. As used herein,“configured to” denotes existing characteristics of a system, apparatus,structure, article, element, component, or hardware which enable thesystem, apparatus, structure, article, element, component, or hardwareto perform the specified function without further modification. Forpurposes of this disclosure, a system, apparatus, structure, article,element, component, or hardware described as being “configured to”perform a particular function may additionally or alternatively bedescribed as being “adapted to” and/or as being “operative to” performthat function.

Illustrative, non-exhaustive examples, which may or may not be claimed,of the subject matter according the present disclosure are providedbelow.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4-7,9-12, and 15-17, feedstock line 100 for additive manufacturing of object136 is disclosed. Feedstock line 100 has a feedstock-line length andexterior surface 180, defining interior volume 182 of feedstock line100. Feedstock line 100 comprises elongate filaments 104, resin 124, andoptical direction modifiers 123. Elongate filaments 104 extend along atleast a portion of the feedstock-line length. Resin 124 covers elongatefilaments 104. Optical direction modifiers 123 each extend along only aportion of the feedstock-line length. Optical direction modifiers 123are covered by resin 124 and are interspersed among elongate filaments104. Each of optical direction modifiers 123 has outer surface 184. Eachof optical direction modifiers 123 is configured such that whenelectromagnetic radiation 118 strikes outer surface 184 from a firstdirection, at least a portion of electromagnetic radiation 118 departsouter surface 184 in a second direction that is at an angle to the firstdirection to irradiate, in interior volume 182 of feedstock line 100,resin 124 that, due at least in part to elongate filaments 104, is notdirectly accessible to electromagnetic radiation 118, incident onexterior surface 180 of feedstock line 100. The preceding subject matterof this paragraph characterizes example 1 of the present disclosure.

Inclusion of optical direction modifiers 123 in feedstock line 100facilitates penetration of electromagnetic radiation 118 into interiorvolume 182 of feedstock line 100 for irradiation of resin 124, despiteregions of resin 124 being in the shadows of elongate filaments 104 castby the direct (i.e., line-of-sight) application of electromagneticradiation 118. In other words, even when electromagnetic radiation 118is shielded from directly reaching all regions of resin 124, opticaldirection modifiers 123 will redirect electromagnetic radiation 118 todisperse or scatter electromagnetic radiation 118 to indirectly reachregions of resin 124. As a result, feedstock line 100 may be more easilycured with electromagnetic radiation 118, may be more evenly cured withelectromagnetic radiation 118, may be more thoroughly cured withelectromagnetic radiation 118, and/or may be more quickly cured withelectromagnetic radiation 118. This configuration of feedstock line 100is particularly well suited for additive manufacturing of the fusedfilament fabrication variety, in which feedstock line 100 is dispensedby a print head, or nozzle, and a source of curing energy (e.g.,electromagnetic radiation 118) directs the curing energy at feedstockline 100 as it is being dispensed to cure resin 124 in situ.

Elongate filaments 104 additionally or alternatively may be described asreinforcement filaments or fibers, and may be constructed of anysuitable material, illustrative and non-exclusive examples of whichinclude (but are not limited to) fibers, carbon fibers, glass fibers,synthetic organic fibers, aramid fibers, natural fibers, wood fibers,boron fibers, silicon-carbide fibers, optical fibers, fiber bundles,fiber tows, fiber weaves, wires, metal wires, conductive wires, and wirebundles. Feedstock line 100 may include a single configuration, or type,of elongate filaments 104 or may include more than one configuration, ortype, of elongate filaments 104. In some examples, elongate filaments104 may individually and collectively extend for the entire, orsubstantially the entire, feedstock-line length, and thus may bedescribed as continuous elongate filaments or as full-length elongatefilaments. Additionally or alternatively elongate filaments 104 mayindividually extend for only a portion of the feedstock-line length, andthus may be described as partial-length elongate filaments ornon-continuous elongate filaments. Examples of partial-length elongatefilaments include (but are not limited to) so-called chopped fibers.

Resin 124 may include any suitable material that is configured to becured, or hardened, as a result of cross-linking of polymer chains, suchas responsive to an application of electromagnetic radiation 118. Forexample, electromagnetic radiation 118, or curing energy, may compriseone or more of ultraviolet light, visible light, infrared light, x-rays,electron beams, and microwaves, and resin 124 may take the form of oneor more of a polymer, a resin, a thermoplastic, a thermoset, aphotopolymer, an ultra-violet photopolymer, a visible-lightphotopolymer, an infrared-light photopolymer, and an x-ray photopolymer.As used herein, a photopolymer is a polymer that is configured to becured in the presence of light, such as one or more of ultra-violetlight, visible-light, infrared-light, and x-rays. However, as discussed,inclusion of optical direction modifiers 123 in feedstock line 100specifically facilitates the penetration of electromagnetic radiation118 into the shadows of elongate filaments 104, and thus electromagneticradiation 118 typically will be of a wavelength that does not penetrateelongate filaments 104, and resin 124 typically will be a photopolymer.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4-7,elongate filaments 104 are opaque to electromagnetic radiation 118. Thepreceding subject matter of this paragraph characterizes example 2 ofthe present disclosure, wherein example 2 also includes the subjectmatter according to example 1, above.

Elongate filaments 104 typically will be selected for strengthproperties and not for light-transmissivity properties. For example,carbon fibers are often used in fiber-reinforced composite structures,and carbon fibers are opaque to ultra-violet and visible light.Accordingly, elongate filaments 104 that are opaque to electromagneticradiation 118 are well suited for inclusion in feedstock line 100, asoptical direction modifiers 123 operatively will disperseelectromagnetic radiation 118 into the shadows of elongate filaments104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5, 7, and9-12, optical direction modifiers 123 comprise partial-length opticalwaveguides 122. Each of partial-length optical waveguides 122 comprisespartial-length optical core 138. Partial-length optical core 138 of eachof partial-length optical waveguides 122 comprises firstpartial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, opposite firstpartial-length-optical-core end face 140, and partial-length peripheralsurface 144, extending between first partial-length-optical-core endface 140 and second partial-length-optical-core end face 142. Each ofpartial-length optical waveguides 122 is configured such that whenelectromagnetic radiation 118 enters partial-length optical core 138 viaat least one of first partial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, or partial-length peripheralsurface 144, at least a portion of electromagnetic radiation 118 exitspartial-length optical core 138 via partial-length peripheral surface144 to irradiate, in interior volume 182 of feedstock line 100, resin124 that, due at least in part to elongate filaments 104, is notdirectly accessible to electromagnetic radiation 118, incident onexterior surface 180 of feedstock line 100. The preceding subject matterof this paragraph characterizes example 3 of the present disclosure,wherein example 3 also includes the subject matter according to example1 or 2, above.

Partial-length optical waveguides 122 may be cost effective to create,such as according to the various methods disclosed here. Moreover, bybeing interspersed among elongate filaments 104, partial-length opticalwaveguides 122 may directly receive electromagnetic radiation 118 anddeliver electromagnetic radiation 118 into the shadows of elongatefilaments 104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5, 7, and9-12, feedstock line 100 is configured such that when electromagneticradiation 118 enters interior volume 182 of feedstock line 100 viaexterior surface 180 of feedstock line 100, electromagnetic radiation118 enters at least one of partial-length optical waveguides 122 via atleast one of partial-length peripheral surface 144, firstpartial-length-optical-core end face 140, or secondpartial-length-optical-core end face 142 of at least one ofpartial-length optical waveguides 122. The preceding subject matter ofthis paragraph characterizes example 4 of the present disclosure,wherein example 4 also includes the subject matter according to example3, above.

In other words, in some examples of feedstock line 100, partial-lengthoptical waveguides 122 are positioned within interior volume 182 offeedstock line 100 such that at least one of partial-length peripheralsurface 144, first partial-length-optical-core end face 140, or secondpartial-length-optical-core end face 142 is within the line of sight ofelectromagnetic radiation 118 to receive electromagnetic radiation 118directed to exterior surface 180 of feedstock line 100 and thendisperse, or scatter, electromagnetic radiation 118 within interiorvolume 182.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 9-11,partial-length optical core 138 has a partial-length-optical-corerefractive index. Each of partial-length optical waveguides 122 furthercomprises partial-length-optical-core cladding 160, at least partiallycovering partial-length optical core 138. Partial-length-optical-corecladding 160 comprises at least first partial-length-optical-corecladding resin 162, having a partial-length-optical-corefirst-cladding-resin refractive index. Partial-length-optical-corecladding 160 is non-uniform along each of partial-length opticalwaveguides 122. The partial-length-optical-core refractive index isgreater than the partial-length-optical-core first-cladding-resin resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 5 of the present disclosure, wherein example 5also includes the subject matter according to example 3 or 4, above.

By being non-uniform along the length of partial-length opticalwaveguides 122, electromagnetic radiation 118 is permitted to exitpartial-length optical core 138 via partial-length peripheral surface144. Moreover, by first partial-length-optical-core cladding resin 162having a refractive index that is less than that of partial-lengthoptical core 138, electromagnetic radiation 118, upon enteringpartial-length optical core 138, is trapped within partial-lengthoptical core 138 other than the regions where firstpartial-length-optical-core cladding resin 162 is not present. As aresult, partial-length optical waveguides 122 may be constructed toprovide a desired amount of electromagnetic radiation 118, exitingvarious positions along partial-length peripheral surface 144, such asto ensure a desired amount of electromagnetic radiation 118, penetratingthe shadows of elongate filaments 104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 10 and11, partial-length peripheral surface 144 of partial-length optical core138 of each of partial-length optical waveguides 122 haspartial-length-peripheral-surface regions 129 devoid of firstpartial-length-optical-core cladding resin 162.Partial-length-optical-core cladding 160 further comprises secondpartial-length-optical-core cladding resin 164, having apartial-length-optical-core second-cladding-resin refractive index.Second partial-length-optical-core cladding resin 164 coverspartial-length-peripheral-surface regions 129 of partial-lengthperipheral surface 144. The partial-length-optical-coresecond-cladding-resin refractive index is greater than thepartial-length-optical-core first-cladding-resin refractive index. Thepreceding subject matter of this paragraph characterizes example 6 ofthe present disclosure, wherein example 6 also includes the subjectmatter according to example 5, above.

By covering partial-length-peripheral-surface regions 129 with secondpartial-length-optical-core cladding resin 164, a desired refractiveindex thereof may be selected to optimize how electromagnetic radiation118 exits partial-length peripheral surface 144. Additionally oralternatively, with partial-length-peripheral-surface regions 129covered with second partial-length-optical-core cladding resin 164, theintegrity of first partial-length-optical-core cladding resin 162 may beensured, such that it does not peel or break off during storage ofpartial-length optical waveguides 122 and during construction offeedstock line 100.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 11, secondpartial-length-optical-core cladding resin 164 also covers firstpartial-length-optical-core cladding resin 162. The preceding subjectmatter of this paragraph characterizes example 7 of the presentdisclosure, wherein example 7 also includes the subject matter accordingto example 6, above.

Partial-length optical waveguides 122 according to example 7 may be moreeasily manufactured, in that partial-length optical core 138 with firstpartial-length-optical-core cladding resin 162 simply may be fullycoated with second partial-length-optical-core cladding resin 164.Additionally or alternatively, the integrity of partial-length opticalwaveguides 122 may be maintained during storage thereof and duringconstruction of feedstock line 100.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 10 and11, resin 124 has a resin refractive index. The resin refractive indexis greater than the partial-length-optical-core second-cladding-resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 8 of the present disclosure, wherein example 8also includes the subject matter according to example 6 or 7, above.

Because second partial-length-optical-core cladding resin 164 has arefractive index less than that of resin 124, electromagnetic radiation118 will be permitted to exit second partial-length-optical-corecladding resin 164 to penetrate and cure resin 124 when feedstock line100 is being used to additively manufacture object 136.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 12,partial-length peripheral surface 144 of partial-length optical core 138of each of partial-length optical waveguides 122 has a surface roughnessthat is selected such that when electromagnetic radiation 118 enterspartial-length optical core 138 via at least one of firstpartial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, or partial-length peripheralsurface 144, at least a portion of electromagnetic radiation 118 exitspartial-length optical core 138 via partial-length peripheral surface144 to irradiate, in interior volume 182 of feedstock line 100, resin124 that, due at least in part to elongate filaments 104, is notdirectly accessible to electromagnetic radiation 118, incident onexterior surface 180 of feedstock line 100. The preceding subject matterof this paragraph characterizes example 9 of the present disclosure,wherein example 9 also includes the subject matter according to example3 or 4, above.

Rather than relying on refractive-index properties of a cladding toensure desired dispersal of electromagnetic radiation 118 frompartial-length optical core 138 via partial-length peripheral surface144, the surface roughness of partial-length peripheral surface 144 isselected such that electromagnetic radiation 118 exits partial-lengthoptical core 138 at desired amounts along the length of partial-lengthperipheral surface 144. For example, the surface roughness may createregions of internal reflection of electromagnetic radiation 118 withinpartial-length optical core 138 and may create regions whereelectromagnetic radiation 118 is permitted to escape partial-lengthoptical core 138.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 12, eachof partial-length optical waveguides 122 is devoid of any cladding thatcovers partial-length optical core 138. The preceding subject matter ofthis paragraph characterizes example 10 of the present disclosure,wherein example 10 also includes the subject matter according to example9, above.

Partial-length optical waveguides 122 without any cladding may be lessexpensive to manufacture than partial-length optical waveguides 122 withcladding. Additionally, the difference of refractive indexes between acladding and resin 124 need not be taken into account when selectingresin 124 for feedstock line 100.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4, 6, 7,and 15-17, optical direction modifiers 123 comprise opticaldirection-modifying particles 186. Optical direction-modifying particles186 are configured to at least one of reflect, refract, diffract, orRayleigh-scatter electromagnetic radiation 118, incident on outersurface 184 of any one of optical direction-modifying particles 186, todisperse, in interior volume 182 of feedstock line 100, electromagneticradiation 118 to irradiate resin 124 that, due at least in part toelongate filaments 104, is not directly accessible to electromagneticradiation 118, incident on exterior surface 180 of feedstock line 100.The preceding subject matter of this paragraph characterizes example 11of the present disclosure, wherein example 11 also includes the subjectmatter according to any one of examples 1 to 10, above.

Inclusion of optical direction-modifying particles 186 that at least oneof reflect, refract, diffract, or Rayleigh-scatter electromagneticradiation 118 provides for dispersion of electromagnetic radiation 118within interior volume 182 for irradiation of resin 124 therein.Moreover, because they are particles, optical direction-modifyingparticles 186 more easily are positioned among elongate filaments 104 ofa bundle, or tow, of elongate filaments 104. In addition, in someexamples, they may be generally uniformly spaced throughout resin 124within interior volume 182 and effectively scatter electromagneticradiation 118 throughout interior volume 182 to penetrate among elongatefilaments 104 and into the shadows cast by elongate filaments 104 whenfeedstock line 100 is being used to additively manufacture object 136.In other examples, optical direction-modifying particles 186 may have agradient of concentration within interior volume 182. Opticaldirection-modifying particles 186 may be of any suitable material, suchthat they reflect, refract, diffract, or Rayleigh-scatterelectromagnetic radiation 118. As illustrative, non-exclusive examples,optical direction-modifying particles 186 may be of alumina, silica,thermoplastic with desired reflective, refractive, diffractive, orRayleigh-scattering properties in connection with electromagneticradiation 118.

In some examples of feedstock line 100, a single type, or configuration,of optical direction-modifying particles 186 may be included. In otherexamples of feedstock line 100, more than one type, or configuration, ofoptical direction-modifying particles 186 may be included, withdifferent types being selected to accomplish different functions, andultimately to collectively scatter electromagnetic radiation 118 evenlythroughout interior volume 182, including into the shadows of elongatefilaments 104. For example, a first type of optical direction-modifyingparticles 186 may be configured to reflect electromagnetic radiation118, a second type of optical direction-modifying particles 186 may beconfigured to refract electromagnetic radiation 118, and a third type ofoptical direction-modifying particles 186 may be configured to diffractelectromagnetic radiation 118.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4, 6, and7, each of elongate filaments 104 has a minimum outer dimension. Each ofoptical direction-modifying particles 186 has a maximum outer dimensionthat is less than one-eighth the minimum outer dimension of any one ofelongate filaments 104. The preceding subject matter of this paragraphcharacterizes example 12 of the present disclosure, wherein example 12also includes the subject matter according to example 11, above.

By having a maximum outer dimension that is less than one-eighth theminimum outer dimension of elongate filaments 104, opticaldirection-modifying particles 186 easily extend among elongate filaments104. Moreover, when feedstock line 100 is being constructed (e.g., bysystem 200 herein or according to method 300 herein), opticaldirection-modifying particles 186 may easily flow with resin 124 into abundle, or tow, of elongate filaments 104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4, 6, 7,and 15-17, each of optical direction-modifying particles 186 has amaximum outer dimension that is less than 1000 nm, 500 nm, 250 nm, or200 nm. The preceding subject matter of this paragraph characterizesexample 13 of the present disclosure, wherein example 13 also includesthe subject matter according to example 11 or 12, above.

Typical reinforcement fibers for composite materials often have adiameter in the range of 5 to 8 microns. By having a maximum outerdimension that is less than 1000 nm (1 micron), 500 nm (0.5 micron), 250nm (0.25 micron), or 200 nm (0.200 micron), optical direction-modifyingparticles 186 easily extend between typical sizes of elongate filaments104. Moreover, when feedstock line 100 is being constructed (e.g., bysystem 200 herein or according to method 300 herein), opticaldirection-modifying particles 186 may easily flow with resin 124 into abundle, or tow, of elongate filaments 104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4, 6, 7,and 15-17, electromagnetic radiation 118 has a wavelength. Each ofoptical direction-modifying particles 186 has a minimum outer dimensionthat is greater than one-fourth the wavelength of electromagneticradiation 118. The preceding subject matter of this paragraphcharacterizes example 14 of the present disclosure, wherein example 14also includes the subject matter according to any one of examples 11 to13, above.

Selecting a minimum outer dimension of optical direction-modifyingparticles 186 that is greater than one-fourth the wavelength ofelectromagnetic radiation 118 ensures that optical direction-modifyingparticles 186 will have the intended effect of causing electromagneticradiation 118 to reflect, refract, or diffract upon hitting opticaldirection-modifying particles 186.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4, 6, 7,and 15-17, each of optical direction-modifying particles 186 has aminimum outer dimension that is greater than or equal to 50 nm or thatis greater than or equal to 100 nm. The preceding subject matter of thisparagraph characterizes example 15 of the present disclosure, whereinexample 15 also includes the subject matter according to any one ofexamples 11 to 14, above.

Ultra-violet light having a wavelength of about 400 nm is often used inconnection with ultra-violet photopolymers. Accordingly, when resin 124comprises or consists of a photopolymer, optical direction-modifyingparticles 186 having a minimum outer dimension that is greater than orequal to 100 nm ensures that optical direction-modifying particles 186will have the intended effect of causing electromagnetic radiation 118to reflect, refract, or diffract upon hitting opticaldirection-modifying particles 186. However, in other examples, a minimumouter dimension as low as 50 nm may be appropriate.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4, 6, and7, optical direction-modifying particles 186 comprise less than 10% byweight of resin 124, less than 5% by weigh of resin 124 t, or less than1% by weight of resin 124 of feedstock line 100. The preceding subjectmatter of this paragraph characterizes example 16 of the presentdisclosure, wherein example 16 also includes the subject matteraccording to any one of examples 11 to 15, above.

By limiting optical direction-modifying particles 186 to the referencedthreshold percentages, resin 124 will operatively flow among elongatefilaments 104 when feedstock line 100 is being constructed (e.g., bysystem 200 herein or according to method 300 herein). In addition,desired properties of resin 124, feedstock line 100, and ultimatelyobject 136 will not be negatively impacted by the presence of opticaldirection-modifying particles 186.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 15-17,outer surfaces 184 of at least some of optical direction-modifyingparticles 186 are faceted. The preceding subject matter of thisparagraph characterizes example 17 of the present disclosure, whereinexample 17 also includes the subject matter according to any one ofexamples 11 to 16, above.

By being faceted, outer surfaces 184 effectively scatter electromagneticradiation 118. As used herein, “faceted” means having a plurality ofplanar, or generally planar, surfaces. In some examples of opticaldirection-modifying particles 186 that are faceted, outer surface 184may have six or more, eight or more, ten or more, 100 or more, or even1000 or more generally planar surfaces. Optical direction-modifyingparticles 186 may be of a material that has a natural crystallinestructure that is faceted.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 15-17,outer surfaces 184 of at least some of optical direction-modifyingparticles 186 have a surface roughness that is selected such that whenelectromagnetic radiation 118 strikes outer surfaces 184,electromagnetic radiation 118 is scattered in interior volume 182 offeedstock line 100 to irradiate resin 124 that, due at least in part toelongate filaments 104, is not directly accessible to electromagneticradiation 118, incident on exterior surface 180 of feedstock line 100.The preceding subject matter of this paragraph characterizes example 18of the present disclosure, wherein example 18 also includes the subjectmatter according to any one of examples 11 to 17, above.

Having a surface roughness selected to scatter electromagnetic radiation118 facilitates the operative irradiation of resin 124 throughoutinterior volume 182, including into the shadows of elongate filaments104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 4, 6, and7, resin 124 has a resin refractive index. At least some of opticaldirection-modifying particles 186 have a particle refractive index. Theparticle refractive index is greater than or less than the resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 19 of the present disclosure, wherein example 19also includes the subject matter according to any one of examples 11 to18, above.

When optical direction-modifying particles 186 have a refractive indexthat is different from (e.g., that is at least 0.001 greater or lessthan) the refractive index of resin 124, electromagnetic radiation 118incident upon the outer surfaces thereof will necessarily leave theouter surfaces at a different angle, and thus will scatter throughoutresin 124, including into the shadows of elongate filaments 104.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 15, atleast some of optical direction-modifying particles 186 are spherical.The preceding subject matter of this paragraph characterizes example 20of the present disclosure, wherein example 20 also includes the subjectmatter according to any one of examples 11 to 19, above.

By being spherical, optical direction-modifying particles 186 may easilybe positioned among elongate filaments 104, and when feedstock line 100is being constructed (e.g., by system 200 herein or according to method300 herein), may easily flow with resin 124 into a bundle, or tow, ofelongate filaments 104.

As used herein, “spherical” includes generally spherical and means thatsuch optical direction-modifying particles 186 have a generally uniformaspect ratio, but are not necessarily perfectly spherical. For example,optical direction-modifying particles 186 that are spherical may befaceted, as discussed herein.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 16, atleast some of optical direction-modifying particles 186 are prismatic.The preceding subject matter of this paragraph characterizes example 21of the present disclosure, wherein example 21 also includes the subjectmatter according to any one of examples 11 to 20, above.

By being prismatic, optical direction-modifying particles 186 may beselected to operatively at least one of reflect, refract, or diffractelectromagnetic radiation 118, as discussed herein.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5, 7, and9-12, feedstock line 100 further comprises at least one full-lengthoptical waveguide 102, extending along all of the feedstock-line length.At least one full-length optical waveguide 102 is covered by resin 124and is interspersed among elongate filaments 104. At least onefull-length optical waveguide 102 comprises full-length optical core110. Full-length optical core 110 comprises firstfull-length-optical-core end face 112, second full-length-optical-coreend face 114, opposite first full-length-optical-core end face 112, andfull-length peripheral surface 116extending between firstfull-length-optical-core end face 112 and secondfull-length-optical-core end face 114. At least one full-length opticalwaveguide 102 is configured such that when electromagnetic radiation 118enters full-length optical core 110 via at least one of firstfull-length-optical-core end face 112, second full-length-optical-coreend face 114, or full-length peripheral surface 116, at least a portionof electromagnetic radiation 118 exits full-length optical core 110 viafull-length peripheral surface 116 to irradiate, in interior volume 182of feedstock line 100, resin 124 that, due at least in part to elongatefilaments 104, is not directly accessible to electromagnetic radiation118, incident on exterior surface 180 of feedstock line 100. Thepreceding subject matter of this paragraph characterizes example 22 ofthe present disclosure, wherein example 22 also includes the subjectmatter according to any one of examples 1 to 21, above.

Inclusion of at least one full-length optical waveguide 102 in feedstockline 100 further facilitates penetration of electromagnetic radiation118 into interior volume 182 of feedstock line 100 for irradiation ofresin 124, despite regions of resin 124 being in the shadows of elongatefilaments 104 cast by the direct (i.e., line-of-sight) application ofelectromagnetic radiation 118. In other words, even when electromagneticradiation 118 is shielded from directly reaching all regions of resin124, at least one full-length optical waveguide 102 may receiveelectromagnetic radiation 118 via one or more of its firstfull-length-optical-core end face 112, its secondfull-length-optical-core end face 114, or its full-length peripheralsurface 116, and disperse electromagnetic radiation 118 via at least itsfull-length peripheral surface 116 to indirectly reach regions of resin124. Not only may at least one full-length optical waveguide 102 serveto disperse electromagnetic radiation 118 into the shadows of elongatefilaments 104, it also may serve to redirect electromagnetic radiation118 to optical direction modifiers 123 for penetration into the shadowsof elongate filaments 104 by at least one full-length optical waveguide102. Additionally or alternatively, optical direction modifiers 123 mayserve to redirect electromagnetic radiation 118 to at least onefull-length optical waveguide 102 for penetration into the shadows ofelongate filaments 104 by at least one full-length optical waveguide102.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5, 7,feedstock line 100 is configured such that when electromagneticradiation 118 enters interior volume 182 of feedstock line 100 viaexterior surface 180 of feedstock line 100, electromagnetic radiation118 enters at least one full-length optical waveguide 102 via at leastone of full-length peripheral surface 116, firstfull-length-optical-core end face 112, or secondfull-length-optical-core end face 114 of full-length optical core 110 ofat least one full-length optical waveguide 102. The preceding subjectmatter of this paragraph characterizes example 23 of the presentdisclosure, wherein example 23 also includes the subject matteraccording to example 22, above.

In other words, in some examples of feedstock line 100, at least onefull-length optical waveguide 102 is positioned within interior volume182 of feedstock line 100 such that at least one of full-lengthperipheral surface 116, first full-length-optical-core end face 112, orsecond full-length-optical-core end face 114 is within the line of sightof electromagnetic radiation 118 to receive electromagnetic radiation118 directed to exterior surface 180 of feedstock line 100 and thendisperse electromagnetic radiation 118 into the shadows of elongatefilaments 104. For example, at least one of full-length peripheralsurface 116, first full-length-optical-core end face 112, or secondfull-length-optical-core end face 114 may be adjacent to exteriorsurface 180 of feedstock line 100.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5, 7, and9-12, at least one full-length optical waveguide 102 is configured suchthat when electromagnetic radiation 118 enters firstfull-length-optical-core end face 112 of full-length optical core 110,an initial portion of electromagnetic radiation 118 exits full-lengthoptical core 110 via full-length peripheral surface 116 and a finalportion of electromagnetic radiation 118, remaining in full-lengthoptical core 110 after the initial portion of electromagnetic radiation118 exits full-length optical core 110, exits full-length optical core110 via second full-length-optical-core end face 114. The precedingsubject matter of this paragraph characterizes example 24 of the presentdisclosure, wherein example 24 also includes the subject matteraccording to example 22 or 23, above.

In other words, in some examples of feedstock line 100, ifelectromagnetic radiation 118 enters first full-length-optical-core endface 112, it will exit both full-length peripheral surface 116 andsecond full-length-optical-core end face 114, as opposed, for example,to electromagnetic radiation 118 being fully emitted via full-lengthperipheral surface 116. Such examples of feedstock line 100 are wellsuited for additive manufacturing systems and methods in whichelectromagnetic radiation 118 is directed at firstfull-length-optical-core end face 112 as feedstock line 100 is beingconstructed and as object 136 is being manufactured. That is, anadditive manufacturing system may be configured to construct feedstockline 100 while object 136 is being manufactured from feedstock line 100,and while electromagnetic radiation 118 is entering firstfull-length-optical-core end face 112. Because electromagnetic radiation118 exits not only full-length peripheral surface 116, but also secondfull-length-optical-core end face 114, it is ensured that sufficientelectromagnetic radiation 118 travels the full length of at least onefull-length optical waveguide 102 to operatively cure resin 124 amongelongate filaments 104 within interior volume 182 of feedstock line 100.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5, 7, and9-12, at least one full-length optical waveguide 102 is configured suchthat the initial portion of electromagnetic radiation 118, which exitsfull-length optical core 110 via full-length peripheral surface 116, isgreater than or equal to the final portion of electromagnetic radiation118, which exits full-length optical core 110 via secondfull-length-optical-core end face 114. The preceding subject matter ofthis paragraph characterizes example 25 of the present disclosure,wherein example 25 also includes the subject matter according to example24, above.

In such configurations, it is ensured that a desired amount ofelectromagnetic radiation 118 exits full-length optical core 110 viafull-length peripheral surface 116 to operatively cure resin 124 amongelongate filaments 104 within interior volume 182 of feedstock line 100,when feedstock line 100 is utilized by an additive manufacturing systemor in an additive manufacturing method.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5 and 7,at least one full-length optical waveguide 102 is at least one ofparallel to, generally parallel to, twisted with, woven with, or braidedwith elongate filaments 104. The preceding subject matter of thisparagraph characterizes example 26 of the present disclosure, whereinexample 26 also includes the subject matter according to any one ofexamples 22 to 25, above.

By at least one full-length optical waveguide 102 being generallyparallel to elongate filaments 104, the reinforcing properties ofelongate filaments 104 within feedstock line 100, and thus within object136 are not materially affected. By being twisted with, woven with, orbraided with elongate filaments 104, at least one full-length opticalwaveguide 102 is interspersed with elongate filaments 104 so thatelectromagnetic radiation 118, exiting at least one full-length opticalwaveguide 102, is delivered to regions of interior volume 182 that arein the shadows of elongated filaments 104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 9-11,full-length optical core 110 has a full-length-optical-core refractiveindex. At least one full-length optical waveguide 102 further comprisesfull-length-optical-core cladding 154, at least partially coveringfull-length optical core 110. Full-length-optical-core cladding 154comprises at least first full-length-optical-core cladding resin 156,having a full-length-optical-core first-cladding-resin refractive index.Full-length-optical-core cladding 154 is non-uniform along at least onefull-length optical waveguide 102. Full-length-optical-core refractiveindex is greater than the full-length-optical-core first-cladding-resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 27 of the present disclosure, wherein example 27also includes the subject matter according to any one of examples 22 to26, above.

By full-length-optical-core cladding 154 being non-uniform along thelength of full-length optical waveguide 102, electromagnetic radiation118 is permitted to exit full-length optical core 110 via full-lengthperipheral surface 116. Moreover, by first full-length-optical-corecladding resin 156 having a refractive index that is less than that offull-length optical core 110, electromagnetic radiation 118, uponentering full-length optical core 110, is trapped within full-lengthoptical core 110 other than the regions where firstfull-length-optical-core cladding resin 156 is not present. As a result,at least one full-length optical waveguide 102 may be constructed toprovide a desired amount of electromagnetic radiation 118, exitingvarious positions along full-length peripheral surface 116, such as toensure a desired amount of electromagnetic radiation 118, penetratingthe shadows of elongate filaments 104.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 10 and11, full-length peripheral surface 116 hasfull-length-peripheral-surface regions 127 devoid of firstfull-length-optical-core cladding resin 156. Full-length-optical-corecladding 154 further comprises second full-length-optical-core claddingresin 158, having a full-length-optical-core second-cladding-resinrefractive index. Second full-length-optical-core cladding resin 158covers full-length-peripheral-surface regions 127 of full-lengthperipheral surface 116. The full-length-optical-coresecond-cladding-resin refractive index is greater than thefull-length-optical-core first-cladding-resin refractive index. Thepreceding subject matter of this paragraph characterizes example 28 ofthe present disclosure, wherein example 28 also includes the subjectmatter according to example 27, above.

By covering full-length-peripheral-surface regions 127 with secondfull-length-optical-core cladding resin 158, a desired refractive indexthereof may be selected to optimize how electromagnetic radiation 118exits full-length peripheral surface 116. Additionally or alternatively,with full-length-peripheral-surface regions 127 covered with secondfull-length-optical-core cladding resin 158, the integrity of firstfull-length-optical-core cladding resin 156 may be ensured, such that itdoes not peel or break off during storage of at least one full-lengthoptical waveguide 102 and during construction of feedstock line 100.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 11, secondfull-length-optical-core cladding resin 158 also covers firstfull-length-optical-core cladding resin 156. The preceding subjectmatter of this paragraph characterizes example 29 of the presentdisclosure, wherein example 29 also includes the subject matteraccording to example 28, above.

Full-length optical waveguides according to example 29 may be moreeasily manufactured, in that full-length optical core 110 with firstfull-length-optical-core cladding resin 156 simply may be fully coatedwith second full-length-optical-core cladding resin 158. Additionally oralternatively, the integrity of full-length optical waveguides may bemaintained during storage thereof and during construction of feedstockline 100.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 10 and11, resin 124 has a resin refractive index. The resin refractive indexis greater than the full-length-optical-core second-cladding-resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 30 of the present disclosure, wherein example 30also includes the subject matter according to example 28 or 29, above.

Because second full-length-optical-core cladding resin 158 has arefractive index less than that of resin 124, electromagnetic radiation118 will be permitted to exit second full-length-optical-core claddingresin 158 to penetrate and cure resin 124 when feedstock line 100 isused to additively manufacture object 136.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 12,full-length peripheral surface 116 has a surface roughness that isselected such that when electromagnetic radiation 118 enters full-lengthoptical core 110 via at least one of first full-length-optical-core endface 112, second full-length-optical-core end face 114, or full-lengthperipheral surface 116, at least a portion of electromagnetic radiation118 exits full-length optical core 110 via full-length peripheralsurface 116 to irradiate, in interior volume 182 of feedstock line 100,resin 124 that, due at least in part to elongate filaments 104, is notdirectly accessible to electromagnetic radiation 118, incident onexterior surface 180 of feedstock line 100. The preceding subject matterof this paragraph characterizes example 31 of the present disclosure,wherein example 31 also includes the subject matter according to any oneof examples 22 to 26, above.

Rather than relying on refractive-index properties of a cladding toensure desired dispersal of electromagnetic radiation 118 fromfull-length optical core 110 via full-length peripheral surface 116, thesurface roughness of full-length peripheral surface 116 is selected suchthat electromagnetic radiation 118 exits full-length optical core 110 atdesired amounts along the length of full-length peripheral surface 116.For example, the surface roughness may create regions of internalreflection of electromagnetic radiation 118 within full-length opticalcore 110 and may create regions where electromagnetic radiation 118 ispermitted to escape full-length optical core 110.

Referring generally to FIG. 1 and particularly to, e.g., FIG. 12, atleast one full-length optical waveguide 102 is devoid of any claddingthat covers full-length optical core 110. The preceding subject matterof this paragraph characterizes example 32 of the present disclosure,wherein example 32 also includes the subject matter according to example31, above.

Full-length optical waveguides without any cladding may be lessexpensive to manufacture than full-length optical waveguides withcladding. Additionally, the difference of refractive indexes between acladding and resin 124 need not be taken into account when selectingresin 124 for feedstock line 100.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5 and 7,at least one full-length optical waveguide 102 is a plurality offull-length optical waveguides, interspersed among elongate filaments104. The preceding subject matter of this paragraph characterizesexample 33 of the present disclosure, wherein example 33 also includesthe subject matter according to any one of examples 22 to 32, above.

By including a plurality of full-length optical waveguides, interspersedamong elongate filaments 104, such as among a bundle, or tow, ofelongate filaments, a desired penetration of electromagnetic radiation118 into the shadows of elongate filaments 104 is be ensured.

Referring generally to FIG. 1 and particularly to, e.g., FIGS. 5 and 7,elongate filaments 104 are at least one of twisted with, woven with, orbraided with the plurality of full-length optical waveguides. Thepreceding subject matter of this paragraph characterizes example 34 ofthe present disclosure, wherein example 34 also includes the subjectmatter according to example 33, above.

By being twisted with, woven with, or braided with elongate filaments104, the plurality of full-length optical waveguides is interspersedwith elongate filaments 104 so that electromagnetic radiation 118,exiting the full-length optical waveguides, is delivered to regions ofinterior volume 182 that are in the shadows of elongated filaments 104.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 13 and14, system 200 for creating feedstock line 100 for additivemanufacturing of object 136 is disclosed. Feedstock line 100 has afeedstock-line length. System 200 comprises prepreg-tow supply 202,prepreg-tow separator 210, optical-direction-modifier supply 216,combiner 212, and at least one heater 220. Prepreg-tow supply 202 isconfigured to dispense precursor prepreg tow 208, comprising elongatefilaments 104 and resin 124, covering elongate filaments 104.Prepreg-tow separator 210 is configured to separate precursor prepregtow 208, dispensed from prepreg-tow supply 202, into individual ones ofelongate filaments 104, at least partially covered with resin 124, orinto subsets 214 of elongate filaments 104, at least partially coveredwith resin 124. Each of subsets 214 comprises a plurality of elongatefilaments 104. Optical-direction-modifier supply 216 is configured todispense optical direction modifiers 123 to be applied to the individualones of elongate filaments 104, at least partially covered with resin124, or to subsets 214 of elongate filaments 104, at least partiallycovered by resin 124, originating from prepreg-tow separator 210. Eachof optical direction modifiers 123 has outer surface 184, and each ofoptical direction modifiers 123 is configured such that whenelectromagnetic radiation 118 strikes outer surface 184 from a firstdirection, at least a portion of electromagnetic radiation 118 departsouter surface 184 in a second direction that is at an angle to the firstdirection. Combiner 212 is configured to combine the individual ones ofelongate filaments 104, at least partially covered with resin 124, andoptical direction modifiers 123, dispensed by optical-direction-modifiersupply 216, or to combine subsets 214 of elongate filaments 104, atleast partially covered with resin 124, and optical direction modifiers123, dispensed by optical-direction-modifier supply 216, into derivativeprepreg tow 209 so that optical direction modifiers 123 are interspersedamong elongate filaments 104. At least one heater 220 is configured toheat at least one of (i) resin 124 in precursor prepreg tow 208,dispensed from prepreg-tow supply 202, to a first threshold temperatureto facilitate separation of precursor prepreg tow 208 by prepreg-towseparator 210 into the individual ones of elongate filaments 104 or intosubsets 214 of elongate filaments 104; (ii) resin 124 that at leastpartially covers the individual ones of elongate filaments 104 orsubsets 214 of elongate filaments 104, originating from prepreg-towseparator 210, to a second threshold temperature to cause wet-out ofoptical direction modifiers 123 and elongate filaments 104 in derivativeprepreg tow 209 by resin 124; or (iii) resin 124 that at least partiallycovers elongate filaments 104 in derivative prepreg tow 209, originatingfrom combiner 212, to a third threshold temperature to cause wet-out ofoptical direction modifiers 123 and elongate filaments 104 in derivativeprepreg tow 209 by resin 124. The preceding subject matter of thisparagraph characterizes example 35 of the present disclosure.

Creating feedstock line 100 from precursor prepreg tow 208 permits theuse of off-the-shelf prepreg reinforcement fiber tows. Prepreg-towseparator 210 separates precursor prepreg tow 208 into individual onesof elongate filaments 104 that are at least partially covered with resin124 or into subsets 214 of elongate filaments 104 that are at leastpartially covered with resin 124, so that optical direction modifiers123 may be operatively interspersed with elongate filaments 104.Combiner 212 then combines elongate filaments 104 and optical directionmodifiers 123, together with resin 124, into derivative prepreg tow 209to ultimately become feedstock line 100. At least one heater 220 heatsresin 124 to facilitate one or both of separation of precursor prepregtow 208 or wetting-out of elongate filaments 104 and optical directionmodifiers 123 in derivative prepreg tow 209.

Precursor prepreg tow 208 may take any suitable form depending on thedesired properties of feedstock line 100. As mentioned, precursorprepreg tow 208 may be (but is not required to be) an off-the-shelfprecursor prepreg tow, with such examples including tows having 1000,3000, 6000, 12000, 24000, or 48000 continuous individual fibers withinthe tow, but other examples also may be used.

Prepreg-tow separator 210 may take any suitable configuration, such thatit is configured to operatively separate precursor prepreg tow 208 intoindividual ones of elongate filaments 104 or subsets 214 thereof. Forexample, prepreg-tow separator 210 may comprise at least one of a knife,an air knife, a comb, a mesh, a screen, a series of polished idlers, andother mechanisms known in the art.

Combiner 212 may take any suitable configuration, such that it isconfigured to operatively combine elongate filaments 104 with opticaldirection modifiers 123, such that optical direction modifiers 123become interspersed among elongate filaments 104, and such that elongatefilaments 104 and optical direction modifiers 123 are at least partiallycovered by resin 124. For example, combiner 212 may at least one oftwist, weave, braid, or otherwise bundle elongate filaments 104.Combiner 212 also may include a fixator, such as a mesh or screen,through which elongate filaments 104, and which prevents the twisting,weaving, braiding, or bundling from propagating upstream of combiner212.

Heater 220 may take any suitable configuration, such that it isconfigured to heat resin 124 at an operative location as feedstock line100 is being created. In some examples, heater 220 may utilize a heatedfluid stream, such as a heated gas stream to heat resin 124.Additionally or alternatively, in some examples, heater 220 may comprisea resistive, or other type of, heater to heat resin 124, such as itpasses through prepreg-tow separator 210 or combiner 212, such as withprepreg-tow separator 210 comprising heater 220 or combiner 212comprising heater 220, respectively.

In some examples, two or more of the first threshold temperature, thesecond threshold temperature, or the third threshold temperature may bethe same temperature. In other examples, two or more of the firstthreshold temperature, the second threshold temperature, or the thirdthreshold temperature may be different temperatures.

Referring generally to FIG. 2, elongate filaments 104 are opaque toelectromagnetic radiation 118. The preceding subject matter of thisparagraph characterizes example 36 of the present disclosure, whereinexample 36 also includes the subject matter according to example 35,above.

As discussed, elongate filaments 104 that are opaque to electromagneticradiation 118 may be well suited for inclusion in feedstock line 100, asoptical direction modifiers 123 operatively will disperseelectromagnetic radiation 118 into the shadows of elongate filaments 104when feedstock line 100 is being used to additively manufacture object136 with in situ curing thereof.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 9-12,optical direction modifiers 123 comprise partial-length opticalwaveguides 122. Each of partial-length optical waveguides 122 comprisespartial-length optical core 138. Partial-length optical core 138 of eachof partial-length optical waveguides 122 comprises firstpartial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, opposite firstpartial-length-optical-core end face 140, and partial-length peripheralsurface 144, extending between first partial-length-optical-core endface 140 and second partial-length-optical-core end face 142. Each ofpartial-length optical waveguides 122 is configured such that whenelectromagnetic radiation 118 enters partial-length optical core 138 viaat least one of first partial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, or partial-length peripheralsurface 144, at least a portion of electromagnetic radiation 118 exitspartial-length optical core 138 via partial-length peripheral surface144. The preceding subject matter of this paragraph characterizesexample 37 of the present disclosure, wherein example 37 also includesthe subject matter according to example 35 or 36, above.

As discussed, partial-length optical waveguides 122 may be costeffective to create, such as according to the various methods disclosedhere. Moreover, by being interspersed among elongate filaments 104,partial-length optical waveguides 122 may directly receiveelectromagnetic radiation 118 and deliver electromagnetic radiation 118into the shadows of elongate filaments 104.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 9-11,partial-length optical core 138 has a partial-length-optical-corerefractive index. Each of partial-length optical waveguides 122 furthercomprises partial-length-optical-core cladding 160, at least partiallycovering partial-length optical core 138. Partial-length-optical-corecladding 160 comprises at least first partial-length-optical-corecladding resin 162, having a partial-length-optical-corefirst-cladding-resin refractive index. Partial-length-optical-corecladding 160 is non-uniform along each of partial-length opticalwaveguides 122. The partial-length-optical-core refractive index isgreater than the partial-length-optical-core first-cladding-resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 38 of the present disclosure, wherein example 38also includes the subject matter according to example 37, above.

As discussed, by partial-length-optical-core cladding 160 beingnon-uniform along the length of partial-length optical waveguides 122,electromagnetic radiation 118 is permitted to exit partial-lengthoptical core 138 via partial-length peripheral surface 144. Moreover, byfirst partial-length-optical-core cladding resin 162 having a refractiveindex that is less than that of partial-length optical core 138,electromagnetic radiation 118, upon entering partial-length optical core138, is trapped within partial-length optical core 138 other than theregions where first partial-length-optical-core cladding resin 162 isnot present. As a result, partial-length optical waveguides 122 may beconstructed to provide a desired amount of electromagnetic radiation118, exiting various positions along partial-length peripheral surface144, such as to ensure a desired amount of electromagnetic radiation118, penetrating the shadows of elongate filaments 104 when feedstockline 100 is being used to additively manufacture object 136.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 10 and11, partial-length peripheral surface 144 of partial-length optical core138 of each of partial-length optical waveguides 122 haspartial-length-peripheral-surface regions 129 devoid of firstpartial-length-optical-core cladding resin 162.Partial-length-optical-core cladding 160 further comprises secondpartial-length-optical-core cladding resin 164, having apartial-length-optical-core second-cladding-resin refractive index.Second partial-length-optical-core cladding resin 164 coverspartial-length-peripheral-surface regions 129 of partial-lengthperipheral surface 144. The partial-length-optical-coresecond-cladding-resin refractive index is greater than thepartial-length-optical-core first-cladding-resin refractive index. Thepreceding subject matter of this paragraph characterizes example 39 ofthe present disclosure, wherein example 39 also includes the subjectmatter according to example 38, above.

As discussed, by covering partial-length-peripheral-surface regions 129with second partial-length-optical-core cladding resin 164, a desiredrefractive index thereof may be selected to optimize how electromagneticradiation 118 exits partial-length peripheral surface 144. Additionallyor alternatively, with partial-length-peripheral-surface regions 129covered with second partial-length-optical-core cladding resin 164, theintegrity of first partial-length-optical-core cladding resin 162 may beensured, such that it does not peel or break off during storage ofpartial-length optical waveguides 122 and during construction offeedstock line 100.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 11, secondpartial-length-optical-core cladding resin 164 also covers firstpartial-length-optical-core cladding resin 162. The preceding subjectmatter of this paragraph characterizes example 40 of the presentdisclosure, wherein example 40 also includes the subject matteraccording to example 39, above.

As discussed, partial-length optical waveguides 122, such as accordingto example 40, may be more easily manufactured, in that partial-lengthoptical core 138 with first partial-length-optical-core cladding resin162 simply may be fully coated with second partial-length-optical-corecladding resin 164. Additionally or alternatively, the integrity ofpartial-length optical waveguides 122 may be maintained during storagethereof and during construction of feedstock line 100.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 10 and11, resin 124 has a resin refractive index. The resin refractive indexis greater than the partial-length-optical-core second-cladding-resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 41 of the present disclosure, wherein example 41also includes the subject matter according to example 39 or 40, above.

Again, because second partial-length-optical-core cladding resin 164 hasa refractive index less than that of resin 124, electromagneticradiation 118 will be permitted to exit secondpartial-length-optical-core cladding resin 164 to penetrate and cureresin 124 when feedstock line 100 is being used to additivelymanufacture object 136.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 12,partial-length peripheral surface 144 of partial-length optical core 138of each of partial-length optical waveguides 122 has a surface roughnessthat is selected such that when electromagnetic radiation 118 enterspartial-length optical core 138 via at least one of firstpartial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, or partial-length peripheralsurface 144, at least a portion of electromagnetic radiation 118 exitspartial-length optical core 138 via partial-length peripheral surface144. The preceding subject matter of this paragraph characterizesexample 42 of the present disclosure, wherein example 42 also includesthe subject matter according to example 37 or 38, above.

Again, rather than relying on refractive-index properties of a claddingto ensure desired dispersal of electromagnetic radiation 118 frompartial-length optical core 138 via partial-length peripheral surface144, the surface roughness of partial-length peripheral surface 144 isselected such that electromagnetic radiation 118 exits partial-lengthoptical core 138 at desired amounts along the length of partial-lengthperipheral surface 144. For example, the surface roughness may createregions of internal reflection of electromagnetic radiation 118 withinpartial-length optical core 138 and may create regions whereelectromagnetic radiation 118 is permitted to escape partial-lengthoptical core 138.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 12, eachof partial-length optical waveguides 122 is devoid of any cladding thatcovers partial-length optical core 138. The preceding subject matter ofthis paragraph characterizes example 43 of the present disclosure,wherein example 43 also includes the subject matter according to example42, above.

Again, partial-length optical waveguides 122 without any cladding may beless expensive to manufacture than partial-length optical waveguides 122with cladding. Additionally, the difference of refractive indexesbetween a cladding and resin 124 need not be taken into account whenselecting resin 124 for feedstock line 100.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 15-17,optical direction modifiers 123 comprise optical direction-modifyingparticles 186. Optical direction-modifying particles 186 are configuredto at least one of reflect, refract, diffract, or Rayleigh-scatterelectromagnetic radiation 118, incident on outer surface 184 of any oneof optical direction-modifying particles 186 to disperse electromagneticradiation 118. The preceding subject matter of this paragraphcharacterizes example 44 of the present disclosure, wherein example 44also includes the subject matter according to any one of examples 35 to43, above.

As discussed, inclusion of optical direction-modifying particles 186that at least one of reflect, refract, diffract, or Rayleigh-scatterelectromagnetic radiation 118 provides for further dispersion ofelectromagnetic radiation 118 within interior volume 182 for irradiationof resin 124 therein when feedstock line 100 is being used to additivelymanufacture object 136. Moreover, because they are particles, opticaldirection-modifying particles 186 more easily are interspersed amongelongate filaments 104 when applied thereto. In addition, in someexamples of feedstock line 100, they may be generally uniformly spacedthroughout resin 124 within interior volume 182 and effectively scatterelectromagnetic radiation 118 throughout interior volume 182 topenetrate among elongate filaments 104 and into the shadows cast byelongate filaments 104 when feedstock line 100 is being used toadditively manufacture object 136. In other examples of feedstock line100, optical direction-modifying particles 186 may have a gradient ofconcentration within interior volume 182

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 4, 6, 7,and 15-17, each of elongate filaments 104 has a minimum outer dimension.Each of optical direction-modifying particles 186 has a maximum outerdimension that is less than one-eighth the minimum outer dimension ofany one of elongate filaments 104. The preceding subject matter of thisparagraph characterizes example 45 of the present disclosure, whereinexample 45 also includes the subject matter according to example 44,above.

Again, by having a maximum outer dimension that is less than one-eighththe minimum outer dimension of elongate filaments 104, opticaldirection-modifying particles 186 are easily dispersed among elongatefilaments 104. Moreover, optical direction-modifying particles 186 mayeasily flow with resin 124 to operatively disperse opticaldirection-modifying particles 186 throughout feedstock line 100,including into the shadows of elongate filaments 104.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 15-17,each of optical direction-modifying particles 186 has a maximum outerdimension that is less than 1000 nm, 500 nm, 250 nm, or 200 nm. Thepreceding subject matter of this paragraph characterizes example 46 ofthe present disclosure, wherein example 46 also includes the subjectmatter according to example 44 or 45, above.

As discussed, typical reinforcement fibers for composite materials oftenhave a diameter in the range of 5 to 8 microns. By having a maximumouter dimension that is less than 1000 nm (1 micron), 500 nm (0.5micron), 250 nm (0.25 micron), or 200 nm (0.200 micron), opticaldirection-modifying particles 186 easily extend between typical sizes ofelongate filaments 104. Moreover, optical direction-modifying particles186 may easily flow with resin 124 to operatively disperse opticaldirection-modifying particles 186 throughout feedstock line 100,including into the shadows of elongate filaments 104.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 15-17,electromagnetic radiation 118 has a wavelength. Each of opticaldirection-modifying particles 186 has a minimum outer dimension that isgreater than one-fourth the wavelength of electromagnetic radiation 118.The preceding subject matter of this paragraph characterizes example 47of the present disclosure, wherein example 47 also includes the subjectmatter according to any one of examples 44 to 46, above.

Again, selecting a minimum outer dimension of opticaldirection-modifying particles 186 that is greater than one-fourth thewavelength of electromagnetic radiation 118 that will be used whenadditively manufacturing object 136 ensures that opticaldirection-modifying particles 186 will have the intended effect ofcausing electromagnetic radiation 118 to reflect, refract, or diffractupon hitting optical direction-modifying particles 186.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 15-17,each of optical direction-modifying particles 186 has a minimum outerdimension that is greater than or equal to 50 nm or that is greater thanor equal to 100 nm. The preceding subject matter of this paragraphcharacterizes example 48 of the present disclosure, wherein example 48also includes the subject matter according to any one of examples 44 to47, above.

As discussed, ultra-violet light having a wavelength of about 400 nm isoften used in connection with ultra-violet photopolymers. Accordingly,when resin 124 comprises or consists of a photopolymer, opticaldirection-modifying particles 186 having a minimum outer dimension thatis greater than or equal to 100 nm ensures that opticaldirection-modifying particles 186 will have the intended effect ofcausing electromagnetic radiation 118 to reflect, refract, or diffractupon hitting optical direction-modifying particles 186. However, inother examples, a minimum outer dimension as low as 50 nm may beappropriate.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 1, 4, 6,and 7, in feedstock line 100, optical direction-modifying particles 186comprise less than 10% by weight of resin 124, less than 5% by weight ofresin 124, or less than 1% by weight of resin 124. The preceding subjectmatter of this paragraph characterizes example 49 of the presentdisclosure, wherein example 49 also includes the subject matteraccording to any one of examples 44 to 48, above.

As discussed, by limiting optical direction-modifying particles 186 tothe referenced threshold percentages, resin 124 will operatively flowamong elongate filaments 104 when combiner 212 combines elongatefilaments 104 and optical direction-modifying particles 186. Inaddition, desired properties of resin 124, feedstock line 100, andultimately object 136 will not be negatively impacted by the presence ofoptical direction-modifying particles 186.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 15-17,outer surfaces 184 of at least some of optical direction-modifyingparticles 186 are faceted. The preceding subject matter of thisparagraph characterizes example 50 of the present disclosure, whereinexample 50 also includes the subject matter according to any one ofexamples 44 to 49, above.

Again, by being faceted, outer surfaces 184 effectively scatterelectromagnetic radiation 118.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 15-17,outer surfaces 184 of at least some of optical direction-modifyingparticles 186 have a surface roughness that is selected such that whenelectromagnetic radiation 118 strikes outer surfaces 184,electromagnetic radiation 118 is scattered. The preceding subject matterof this paragraph characterizes example 51 of the present disclosure,wherein example 51 also includes the subject matter according to any oneof examples 44 to 50, above.

As discussed, having a surface roughness selected to scatterelectromagnetic radiation 118 facilitates the operative irradiation ofresin 124 throughout feedstock line 100, including into the shadows ofelongate filaments 104, when feedstock line 100 is being used toadditively manufacture object 136.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 4, 6, and7, resin 124 has a resin refractive index. At least some of opticaldirection-modifying particles 186 have a particle refractive index. Theparticle refractive index is greater than or less than the resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 52 of the present disclosure, wherein example 52also includes the subject matter according to any one of examples 44 to51, above.

Again, when optical direction-modifying particles 186 have a refractiveindex that is different from the refractive index of resin 124,electromagnetic radiation 118 incident upon the outer surfaces thereofwill necessarily leave the outer surfaces at a different angle, and thuswill scatter throughout resin 124, including into the shadows ofelongate filaments 104.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 15, atleast some of optical direction-modifying particles 186 are spherical.The preceding subject matter of this paragraph characterizes example 53of the present disclosure, wherein example 53 also includes the subjectmatter according to any one of examples 44 to 52, above.

Again, by being spherical, optical direction-modifying particles 186easily may be positioned among elongate filaments 104 and may easilyflow with resin 124 as combiner 212 combines elongate filaments 104 andoptical direction-modifying particles 186.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 16, atleast some of optical direction-modifying particles 186 are prismatic.The preceding subject matter of this paragraph characterizes example 54of the present disclosure, wherein example 54 also includes the subjectmatter according to any one of examples 44 to 53, above.

Again, by being prismatic, optical direction-modifying particles 186 maybe selected to operatively at least one of reflect, refract, or diffractelectromagnetic radiation 118, as discussed herein.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 14, system200 further comprises full-length-optical-waveguide supply 204,configured to dispense at least one full-length optical waveguide 102.Combiner 212 is further configured to combine at least one full-lengthoptical waveguide 102, dispensed by full-length-optical-waveguide supply204, with the individual ones of elongate filaments 104, at leastpartially covered with resin 124, or subsets 214 of elongate filaments104, at least partially covered with resin 124, originating fromprepreg-tow separator 210, and optical direction modifiers 123 intoderivative prepreg tow 209 so that at least one full-length opticalwaveguide 102 is interspersed among elongate filaments 104. Thepreceding subject matter of this paragraph characterizes example 55 ofthe present disclosure, wherein example 55 also includes the subjectmatter according to any one of examples 35 to 54, above.

As discussed, inclusion of at least one full-length optical waveguide102 in feedstock line 100 further facilitates penetration ofelectromagnetic radiation 118 into interior volume 182 of feedstock line100 for irradiation of resin 124, despite regions of resin 124 being inthe shadows of elongate filaments 104 cast by the direct (i.e.,line-of-sight) application of electromagnetic radiation 118.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 14, atleast one full-length optical waveguide 102 comprises full-lengthoptical core 110. Full-length optical core 110 comprises firstfull-length-optical-core end face 112, second full-length-optical-coreend face 114, opposite first full-length-optical-core end face 112, andfull-length peripheral surface 116, extending between firstfull-length-optical-core end face 112 and secondfull-length-optical-core end face 114. At least one full-length opticalwaveguide 102 is configured such that when electromagnetic radiation 118enters full-length optical core 110 via at least one of firstfull-length-optical-core end face 112, second full-length-optical-coreend face 114, or full-length peripheral surface 116, at least a portionof electromagnetic radiation 118 exits full-length optical core 110 viafull-length peripheral surface 116. The preceding subject matter of thisparagraph characterizes example 56 of the present disclosure, whereinexample 56 also includes the subject matter according to example 55,above.

As discussed, even when electromagnetic radiation 118 is shielded fromdirectly reaching all regions of resin 124, at least one full-lengthoptical waveguide 102 may receive electromagnetic radiation 118 via oneor more of its first full-length-optical-core end face 112, its secondfull-length-optical-core end face 114, or its full-length peripheralsurface 116, and disperse electromagnetic radiation 118 via at least itsfull-length peripheral surface 116 to indirectly reach regions of resin124. Not only may at least one full-length optical waveguide 102 serveto disperse electromagnetic radiation 118 into the shadows of elongatefilaments 104, it also may serve to redirect electromagnetic radiation118 to optical direction modifiers 123 for penetration into the shadowsof elongate filaments 104 by at least one full-length optical waveguide102. Additionally or alternatively, optical direction modifiers 123 mayserve to redirect electromagnetic radiation 118 to at least onefull-length optical waveguide 102 for penetration into the shadows ofelongate filaments 104 by at least one full-length optical waveguide102.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 9-12, atleast one full-length optical waveguide 102 is configured such that whenelectromagnetic radiation 118 enters first full-length-optical-core endface 112 of full-length optical core 110, an initial portion ofelectromagnetic radiation 118 exits full-length optical core 110 viafull-length peripheral surface 116 and a final portion ofelectromagnetic radiation 118, remaining in full-length optical core 110after the initial portion of electromagnetic radiation 118 exitsfull-length optical core 110, exits full-length optical core 110 viasecond full-length-optical-core end face 114. The preceding subjectmatter of this paragraph characterizes example 57 of the presentdisclosure, wherein example 57 also includes the subject matteraccording to example 56, above.

In other words, in some examples of feedstock line 100, ifelectromagnetic radiation 118 enters first full-length-optical-core endface 112, it will exit both full-length peripheral surface 116 andsecond full-length-optical-core end face 114, as opposed, for example,to electromagnetic radiation 118 being fully emitted via full-lengthperipheral surface 116. As discussed, such examples of feedstock line100 are well suited for additive manufacturing systems and methods inwhich electromagnetic radiation 118 is directed at firstfull-length-optical-core end face 112 as feedstock line 100 is beingconstructed and as object 136 is being manufactured.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 9-12, atleast one full-length optical waveguide 102 is configured such that theinitial portion of electromagnetic radiation 118, which exitsfull-length optical core 110 via full-length peripheral surface 116, isgreater than or equal to the final portion of electromagnetic radiation118, which exits full-length optical core 110 via secondfull-length-optical-core end face 114. The preceding subject matter ofthis paragraph characterizes example 58 of the present disclosure,wherein example 58 also includes the subject matter according to example57, above.

As discussed, in such configurations, it is ensured that a desiredamount of electromagnetic radiation 118 exits full-length optical core110 via full-length peripheral surface 116 to operatively cure resin 124among elongate filaments 104 within interior volume 182 of feedstockline 100 when feedstock line 100 is used to additively manufactureobject 136.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 9-11,full-length optical core 110 has a full-length-optical-core refractiveindex. At least one full-length optical waveguide 102 further comprisesfull-length-optical-core cladding 154, at least partially coveringfull-length optical core 110. Full-length-optical-core cladding 154comprises at least first full-length-optical-core cladding resin 156,having a full-length-optical-core first-cladding-resin refractive index.Full-length-optical-core cladding 154 is non-uniform along at least onefull-length optical waveguide 102. The full-length-optical-corerefractive index is greater than the full-length-optical-corefirst-cladding-resin refractive index. The preceding subject matter ofthis paragraph characterizes example 59 of the present disclosure,wherein example 59 also includes the subject matter according to any oneof examples 56 to 58, above.

As discussed, by full-length-optical-core cladding 154 being non-uniformalong the length of the full-length optical waveguide, electromagneticradiation 118 is permitted to exit full-length optical core 110 viafull-length peripheral surface 116. Moreover, by firstfull-length-optical-core cladding resin 156 having a refractive indexthat is less than that of full-length optical core 110, electromagneticradiation 118, upon entering full-length optical core 110, is trappedwithin full-length optical core 110 other than the regions where firstfull-length-optical-core cladding resin 156 is not present. As a result,the full-length optical waveguide may be constructed to provide adesired amount of electromagnetic radiation 118, exiting variouspositions along full-length peripheral surface 116, such as to ensure adesired amount of electromagnetic radiation 118, penetrating the shadowsof elongate filaments 104 when feedstock line 100 is used to additivelymanufacture object 136.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 10 and11, full-length peripheral surface 116 hasfull-length-peripheral-surface regions 127 devoid of firstfull-length-optical-core cladding resin 156. Full-length-optical-corecladding 154 further comprises second full-length-optical-core claddingresin 158, having a full-length-optical-core second-cladding-resinrefractive index. Second full-length-optical-core cladding resin 158covers full-length-peripheral-surface regions 127 of full-lengthperipheral surface 116. The full-length-optical-coresecond-cladding-resin refractive index is greater than thefull-length-optical-core first-cladding-resin refractive index. Thepreceding subject matter of this paragraph characterizes example 60 ofthe present disclosure, wherein example 60 also includes the subjectmatter according to example 59, above.

As discussed, by covering full-length-peripheral-surface regions 127with second full-length-optical-core cladding resin 158, a desiredrefractive index thereof may be selected to optimize how electromagneticradiation 118 exits full-length peripheral surface 116. Additionally oralternatively, with full-length-peripheral-surface regions 127 coveredwith second full-length-optical-core cladding resin 158, the integrityof first full-length-optical-core cladding resin 156 may be ensured,such that it does not peel or break off during storage of at least onefull-length optical waveguide 102 and during construction of feedstockline 100.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 11, secondfull-length-optical-core cladding resin 158 also covers firstfull-length-optical-core cladding resin 156. The preceding subjectmatter of this paragraph characterizes example 61 of the presentdisclosure, wherein example 61 also includes the subject matteraccording to example 60, above.

As discussed, full-length optical waveguides, such as according toexample 61, may be more easily manufactured, in that full-length opticalcore 110 with first full-length-optical-core cladding resin 156 simplymay be fully coated with second full-length-optical-core cladding resin158. Additionally or alternatively, the integrity of full-length opticalwaveguides may be maintained during storage thereof and duringconstruction of feedstock line 100.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 10 and11, resin 124 has a resin refractive index. The resin refractive indexis greater than the full-length-optical-core second-cladding-resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 62 of the present disclosure, wherein example 62also includes the subject matter according to example 60 or 61, above.

As discussed, because second full-length-optical-core cladding resin 158has a refractive index less than that of resin 124, electromagneticradiation 118 will be permitted to exit second full-length-optical-corecladding resin 158 to penetrate and cure resin 124 when feedstock line100 is used to additively manufacture object 136.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 12,full-length peripheral surface 116 has a surface roughness that isselected such that when electromagnetic radiation 118 enters full-lengthoptical core 110 via at least one of first full-length-optical-core endface 112, second full-length-optical-core end face 114, or full-lengthperipheral surface 116, at least a portion of electromagnetic radiation118 exits full-length optical core 110 via full-length peripheralsurface 116. The preceding subject matter of this paragraphcharacterizes example 63 of the present disclosure, wherein example 63also includes the subject matter according to any one of examples 56 to58, above.

As discussed, rather than relying on refractive-index properties of acladding to ensure desired dispersal of electromagnetic radiation 118from full-length optical core 110 via full-length peripheral surface116, the surface roughness of full-length peripheral surface 116 isselected such that electromagnetic radiation 118 exits full-lengthoptical core 110 at desired amounts along the length of full-lengthperipheral surface 116. For example, the surface roughness may createregions of internal reflection of electromagnetic radiation 118 withinfull-length optical core 110 and may create regions whereelectromagnetic radiation 118 is permitted to escape full-length opticalcore 110.

Referring generally to FIG. 2 and particularly to, e.g., FIG. 12, atleast one full-length optical waveguide 102 is devoid of any claddingthat covers full-length optical core 110. The preceding subject matterof this paragraph characterizes example 64 of the present disclosure,wherein example 64 also includes the subject matter according to example63, above.

As discussed, full-length optical waveguides without any cladding may beless expensive to manufacture than full-length optical waveguides withcladding. Additionally, the difference of refractive indexes between acladding and resin 124 need not be taken into account when selectingresin 124 for feedstock line 100.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 13 and14, combiner 212 is configured to at least one of twist, weave, or braidthe individual ones of elongate filaments 104, originating fromprepreg-tow separator 210, and at least one full-length opticalwaveguide 102, dispensed by full-length-optical-waveguide supply 204, orsubsets 214 of elongate filaments 104, originating from prepreg-towseparator 210, and at least one full-length optical waveguide 102,dispensed by full-length-optical-waveguide supply 204, into derivativeprepreg tow 209. The preceding subject matter of this paragraphcharacterizes example 65 of the present disclosure, wherein example 65also includes the subject matter according to any one of examples 55 to64, above.

As discussed, by being twisted with, woven with, or braided withelongate filaments 104, at least one full-length optical waveguide 102is interspersed with elongate filaments 104 so that electromagneticradiation 118, exiting at least one full-length optical waveguide 102,is delivered to regions of interior volume 182 that are in the shadowsof elongate filaments 104 when feedstock line 100 is used to additivelymanufacture object 136.

As an example, combiner 212 may comprise a spool that winds upderivative prepreg tow 209 while simultaneously twisting derivativeprepreg tow 209. Other mechanisms for twisting, weaving, or braidingmulti-filament structures, as known in the art, also may be used.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 13 and14, system 200 further comprises resin supply 206, configured to provideadditional resin 125 to be applied to at least one of (i) precursorprepreg tow 208, dispensed from prepreg-tow supply 202, (ii) theindividual ones of elongate filaments 104, at least partially coveredwith resin 124, or subsets 214 of elongate filaments 104, at leastpartially covered with resin 124, originating from prepreg-tow separator210, (iii) optical direction modifiers 123, dispensed fromoptical-direction-modifier supply 216, or (iv) derivative prepreg tow209, originating from combiner 212, such that elongate filaments 104 andoptical direction modifiers 123 in derivative prepreg tow 209 arecovered with resin 124 and additional resin 125. The preceding subjectmatter of this paragraph characterizes example 66 of the presentdisclosure, wherein example 66 also includes the subject matteraccording to any one of examples 35 to 65, above.

By applying additional resin 125 to elongate filaments 104 and opticaldirection modifiers 123, full wet-out of elongate filaments 104 andoptical direction modifiers 123 may be achieved in feedstock line 100.

Resin supply 206 may take any suitable configuration, such that it isconfigured to operatively dispense and apply additional resin 125 at anoperative location. For example, resin supply 206 may be configured tospray or mist additional resin 125. Additionally or alternatively, resinsupply 206 may include a reservoir or bath of additional resin 125,through which is pulled at least one of precursor prepreg tow 208,individual ones of elongate filaments 104, subsets 214 of elongatefilaments 104, or derivative prepreg tow 209. In some examples,full-length optical waveguide(s) also may be pulled through such areservoir or bath of additional resin 125.

In some examples, additional resin 125 may be the same as resin 124. Inother examples, additional resin 125 may be different from resin 124.

In some examples, system 200 may further comprise chamber 224 betweenprepreg-tow separator 210 and combiner 212, and through which individualones of elongate filaments 104 or subsets 214 of elongate filaments 104pass as feedstock line 100 is being created. In some such examples, atleast one full-length optical waveguide 102 also extends through chamber224. Moreover, in some such examples, additional resin 125 is applied toat least elongate filaments 104, and in some examples, also to at leastone full-length optical waveguide 102, in chamber 224.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 13 and14, optical-direction-modifier supply 216 and resin supply 206 togetherform combined supply 222, configured to dispense optical directionmodifiers 123 together with additional resin 125. The preceding subjectmatter of this paragraph characterizes example 67 of the presentdisclosure, wherein example 67 also includes the subject matteraccording to example 66, above.

That is, combined supply 222 may dispense optical direction modifiers123 in a volume of additional resin 125. Stated differently, opticaldirection modifiers 123 may be suspended within additional resin 125. Byusing combined supply 222, uniform dispersion of optical directionmodifiers 123 may be ensured, and system 200 may be constructed at adecreased cost. For example, combined supply 222 may spray or mistadditional resin 125 and optical direction modifiers 123 together toapply them to elongate filaments 104, or elongate filaments 104 may bepulled through a bath of additional resin 125 with optical directionmodifiers 123 suspended therein.

Referring generally to FIG. 2 and particularly to, e.g., FIGS. 13 and14, prepreg-tow separator 210 is configured to impart a first electricalcharge to elongate filaments 104 or resin 124 as precursor prepreg tow208 is separated into the individual ones of elongate filaments 104, atleast partially covered with resin 124, or into subsets 214 of elongatefilaments 104, at least partially covered with resin 124. Resin supply206 is configured to impart a second electrical charge to additionalresin 125 when additional resin 125 is applied to at least one of (i)the individual ones of elongate filaments 104, at least partiallycovered with resin 124, or subsets 214 of elongate filaments 104, atleast partially covered with resin 124, and originating from prepreg-towseparator 210, or (ii) derivative prepreg tow 209, originating fromcombiner 212, such that elongate filaments 104 and optical directionmodifiers 123 in derivative prepreg tow 209 are covered with resin 124and additional resin 125. The second electrical charge and the firstelectrical charge have opposite signs. The preceding subject matter ofthis paragraph characterizes example 68 of the present disclosure,wherein example 68 also includes the subject matter according to example66 or 67, above.

By imparting a first electrical charge to elongate filaments 104 orresin 124 and by imparting a second opposite charge to additional resin125 as it is applied to elongate filaments 104, additional resin 125will be electrostatically attracted to elongate filaments 104 or resin124, thereby facilitating wetting of elongate filaments 104 withadditional resin 125.

Referring generally to, e.g., FIGS. 13 and 14, and particularly to FIG.18, method 300 of creating feedstock line 100 for additive manufacturingof object 136 is disclosed. Feedstock line 100 has a feedstock-linelength. Method 300 comprises a step of (block 302) separating precursorprepreg tow 208, comprising elongate filaments 104 and resin 124,covering elongate filaments 104, into individual ones of elongatefilaments 104, at least partially covered with resin 124, or intosubsets 214 of elongate filaments 104, at least partially covered withresin 124. Each of subsets 214 comprises a plurality of elongatefilaments 104. Method 300 also comprises a step of (block 304) applyingoptical direction modifiers 123 to the individual ones of elongatefilaments 104, at least partially covered with resin 124, or to subsets214 of elongate filaments 104, at least partially covered with resin124. Each of optical direction modifiers 123 has outer surface 184, andeach of optical direction modifiers 123 is configured such that whenelectromagnetic radiation 118 strikes outer surface 184 from a firstdirection, at least a portion of electromagnetic radiation 118 departsouter surface 184 in a second direction that is at an angle to the firstdirection. Method 300 further comprises a step of (block 306) combiningoptical direction modifiers 123 with the individual ones of elongatefilaments 104, at least partially covered with resin 124, or subsets 214of elongate filaments 104, at least partially covered with resin 124,into derivative prepreg tow 209 so that optical direction modifiers 123are interspersed among elongate filaments 104. Method 300 additionallycomprises a step of (block 308) heating at least one of (i) (block 310)resin 124 in precursor prepreg tow 208 prior to separating precursorprepreg tow 208 into the individual ones of elongate filaments 104, atleast partially covered with resin 124, or into subsets 214 of elongatefilaments 104, at least partially covered with resin 124, to a firstthreshold temperature to facilitate separating precursor prepreg tow208; (ii) (block 312) resin 124, at least partially covering theindividual ones of elongate filaments 104 or subsets 214 of elongatefilaments 104 following separating precursor prepreg tow 208 into theindividual ones of elongate filaments 104, at least partially coveredwith resin 124, or into subsets 214 of elongate filaments 104, at leastpartially covered with resin 124, and prior to combining opticaldirection modifiers 123 and the individual ones of elongate filaments104, at least partially covered with resin 124, or subsets 214 ofelongate filaments 104, at least partially covered with resin 124, to asecond threshold temperature to cause wet-out of optical directionmodifiers 123 and elongate filaments 104 in derivative prepreg tow 209by resin 124; or (iii) (block 314) resin 124, at least partiallycovering elongate filaments 104 in derivative prepreg tow 209, to athird threshold temperature to cause wet-out of optical directionmodifiers 123 and elongate filaments 104 in derivative prepreg tow 209by resin 124. The preceding subject matter of this paragraphcharacterizes example 69 of the present disclosure.

As discussed in connection with system 200, creating feedstock line 100from precursor prepreg tow 208 permits the use of off-the-shelf prepregreinforcement fiber tows. Separating precursor prepreg tow 208 intoindividual ones of elongate filaments 104 that are at least partiallycovered with resin 124 or into subsets 214 of elongate filaments 104that are at least partially covered with resin 124, enables opticaldirection modifiers 123 to be operatively interspersed among andcombined with elongate filaments 104. Heating resin 124 facilitates oneor both of separation of precursor prepreg tow 208 or wetting-out ofelongate filaments 104 and optical direction modifiers 123 in derivativeprepreg tow 209.

Referring generally to, e.g., FIGS. 13 and 14, according to method 300,elongate filaments 104 are opaque to electromagnetic radiation 118. Thepreceding subject matter of this paragraph characterizes example 70 ofthe present disclosure, wherein example 70 also includes the subjectmatter according to example 69, above.

Again, elongate filaments 104 that are opaque to electromagneticradiation 118 may be well suited for inclusion in feedstock line 100, asoptical direction modifiers 123 operatively will disperseelectromagnetic radiation 118 into the shadows of elongate filaments 104when feedstock line 100 is being used to additively manufacture object136 with in situ curing thereof.

Referring generally to, e.g., FIGS. 9-12, according to method 300,optical direction modifiers 123 comprise partial-length opticalwaveguides 122. Each of partial-length optical waveguides 122 comprisespartial-length optical core 138. Partial-length optical core 138 of eachof partial-length optical waveguides 122 comprises firstpartial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, opposite firstpartial-length-optical-core end face 140, and partial-length peripheralsurface 144, extending between first partial-length-optical-core endface 140 and second partial-length-optical-core end face 142. Each ofpartial-length optical waveguides 122 is configured such that whenelectromagnetic radiation 118 enters partial-length optical core 138 viaat least one of first partial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, or partial-length peripheralsurface 144, at least a portion of electromagnetic radiation 118 exitspartial-length optical core 138 via partial-length peripheral surface144. The preceding subject matter of this paragraph characterizesexample 71 of the present disclosure, wherein example 71 also includesthe subject matter according to example 69 or 70, above.

As discussed, partial-length optical waveguides 122 may be costeffective to create, such as according to the various methods disclosedhere. Moreover, by being interspersed among elongate filaments 104,partial-length optical waveguides 122 may directly receiveelectromagnetic radiation 118 and deliver electromagnetic radiation 118into the shadows of elongate filaments 104.

Referring generally to, e.g., FIGS. 9-11, according to method 300,partial-length optical core 138 has a partial-length-optical-corerefractive index. Each of partial-length optical waveguides 122 furthercomprises partial-length-optical-core cladding 160, at least partiallycovering partial-length optical core 138. Partial-length-optical-corecladding 160 comprises at least first partial-length-optical-corecladding resin 162, having a partial-length-optical-corefirst-cladding-resin refractive index. Partial-length-optical-corecladding 160 is non-uniform along each of partial-length opticalwaveguides 122. Partial-length-optical-core refractive index is greaterthan the partial-length-optical-core first-cladding-resin refractiveindex. The preceding subject matter of this paragraph characterizesexample 72 of the present disclosure, wherein example 72 also includesthe subject matter according to example 71, above.

Again, by partial-length-optical-core cladding 160 being non-uniformalong the length of partial-length optical waveguides 122,electromagnetic radiation 118 is permitted to exit partial-lengthoptical core 138 via partial-length peripheral surface 144. Moreover, byfirst partial-length-optical-core cladding resin 162 having a refractiveindex that is less than that of partial-length optical core 138,electromagnetic radiation 118, upon entering partial-length optical core138, is trapped within partial-length optical core 138 other than theregions where first partial-length-optical-core cladding resin 162 isnot present. As a result, partial-length optical waveguides 122 may beconstructed to provide a desired amount of electromagnetic radiation118, exiting various positions along partial-length peripheral surface144, such as to ensure a desired amount of electromagnetic radiation118, penetrating the shadows of elongate filaments 104 when feedstockline 100 is being used to additively manufacture object 136.

Referring generally to, e.g., FIGS. 10 and 11, according to method 300,partial-length peripheral surface 144 of partial-length optical core 138of each of partial-length optical waveguides 122 haspartial-length-peripheral-surface regions 129 devoid of firstpartial-length-optical-core cladding resin 162.Partial-length-optical-core cladding 160 further comprises secondpartial-length-optical-core cladding resin 164, having apartial-length-optical-core second-cladding-resin refractive index.Second partial-length-optical-core cladding resin 164 coverspartial-length-peripheral-surface regions 129 of partial-lengthperipheral surface 144. The partial-length-optical-coresecond-cladding-resin refractive index is greater than thepartial-length-optical-core first-cladding-resin refractive index. Thepreceding subject matter of this paragraph characterizes example 73 ofthe present disclosure, wherein example 73 also includes the subjectmatter according to example 72, above.

As discussed, by covering partial-length-peripheral-surface regions 129with second partial-length-optical-core cladding resin 164, a desiredrefractive index thereof may be selected to optimize how electromagneticradiation 118 exits partial-length peripheral surface 144. Additionallyor alternatively, with partial-length-peripheral-surface regions 129covered with second partial-length-optical-core cladding resin 164, theintegrity of first partial-length-optical-core cladding resin 162 may beensured, such that it does not peel or break off during storage ofpartial-length optical waveguides 122 and during implementation ofmethod 300.

Referring generally to, e.g., FIG. 11, according to method 300, secondpartial-length-optical-core cladding resin 164 also covers firstpartial-length-optical-core cladding resin 162. The preceding subjectmatter of this paragraph characterizes example 74 of the presentdisclosure, wherein example 74 also includes the subject matteraccording to example 73, above.

As discussed, partial-length optical waveguides 122, such as accordingto example 74, may be more easily manufactured, in that partial-lengthoptical core 138 with first partial-length-optical-core cladding resin162 simply may be fully coated with second partial-length-optical-corecladding resin 164. Additionally or alternatively, the integrity ofpartial-length optical waveguides 122 may be maintained during storagethereof and during implementation of method 300.

Referring generally to, e.g., FIGS. 10 and 11, and particularly to FIG.18, according to method 300, resin 124 has a resin refractive index. Theresin refractive index is greater than the partial-length-optical-coresecond-cladding-resin refractive index. The preceding subject matter ofthis paragraph characterizes example 75 of the present disclosure,wherein example 75 also includes the subject matter according to example73 or 74, above.

Again, because second partial-length-optical-core cladding resin 164 hasa refractive index less than that of resin 124, electromagneticradiation 118 will be permitted to exit secondpartial-length-optical-core cladding resin 164 to penetrate and cureresin 124 when feedstock line 100 is being used to additivelymanufacture object 136.

Referring generally to, e.g., FIG. 12, according to method 300,partial-length peripheral surface 144 of partial-length optical core 138of each of partial-length optical waveguides 122 has a surface roughnessthat is selected such that when electromagnetic radiation 118 enterspartial-length optical core 138 via at least one of firstpartial-length-optical-core end face 140, secondpartial-length-optical-core end face 142, or partial-length peripheralsurface 144, at least a portion of electromagnetic radiation 118 exitspartial-length optical core 138 via partial-length peripheral surface144. The preceding subject matter of this paragraph characterizesexample 76 of the present disclosure, wherein example 76 also includesthe subject matter according to example 71, above.

As discussed, rather than relying on refractive-index properties of acladding to ensure desired dispersal of electromagnetic radiation 118from partial-length optical core 138 via partial-length peripheralsurface 144, the surface roughness of partial-length peripheral surface144 is selected such that electromagnetic radiation 118 exitspartial-length optical core 138 at desired amounts along the length ofpartial-length peripheral surface 144. Again, the surface roughness maycreate regions of internal reflection of electromagnetic radiation 118within partial-length optical core 138 and may create regions whereelectromagnetic radiation 118 is permitted to escape partial-lengthoptical core 138.

Referring generally to, e.g., FIG. 12, according to method 300, each ofpartial-length optical waveguides 122 is devoid of any cladding thatcovers partial-length optical core 138. The preceding subject matter ofthis paragraph characterizes example 77 of the present disclosure,wherein example 77 also includes the subject matter according to example76, above.

As discussed, partial-length optical waveguides 122 without any claddingmay be less expensive to manufacture than partial-length opticalwaveguides 122 with cladding. Additionally, the difference of refractiveindexes between a cladding and resin 124 need not be taken into accountwhen selecting resin 124 for feedstock line 100.

Referring generally to, e.g., FIGS. 15-17, according to method 300,optical direction modifiers 123 comprise optical direction-modifyingparticles 186. Optical direction-modifying particles 186 are configuredto at least one of reflect, refract, diffract, or Rayleigh-scatterelectromagnetic radiation 118, incident on outer surface 184 of any oneof optical direction-modifying particles 186, to disperseelectromagnetic radiation 118. The preceding subject matter of thisparagraph characterizes example 78 of the present disclosure, whereinexample 78 also includes the subject matter according to any one ofexamples 69 to 77, above.

Again, inclusion of optical direction-modifying particles 186 that atleast one of reflect, refract, diffract, or Rayleigh-scatterelectromagnetic radiation 118 provides for further dispersion ofelectromagnetic radiation 118 within interior volume 182 for irradiationof resin 124 therein when feedstock line 100 is being used to additivelymanufacture object 136. Moreover, because they are particles, opticaldirection-modifying particles 186 more easily are interspersed amongelongate filaments 104 when applied thereto. In addition, in someexamples of feedstock line 100, they may be generally uniformly spacedthroughout resin 124 within interior volume 182 and effectively scatterelectromagnetic radiation 118 throughout interior volume 182 topenetrate among elongate filaments 104 and into the shadows cast byelongate filaments 104 when feedstock line 100 is being used toadditively manufacture object 136. In other examples of feedstock line100, optical direction-modifying particles 186 may have a gradient ofconcentration within interior volume 182.

Referring generally to, e.g., FIGS. 4, 6, 7, and 15-17, according tomethod 300, each of elongate filaments 104 has a minimum outerdimension. Each of optical direction-modifying particles 186 has amaximum outer dimension that is less than one-eighth the minimum outerdimension of any one of elongate filaments 104. The preceding subjectmatter of this paragraph characterizes example 79 of the presentdisclosure, wherein example 79 also includes the subject matteraccording to example 78, above.

Again, by having a maximum outer dimension that is less than one-eighththe minimum outer dimension of elongate filaments 104, opticaldirection-modifying particles 186 are easily dispersed among elongatefilaments 104. Moreover, optical direction-modifying particles 186 mayeasily flow with resin 124 to operatively disperse opticaldirection-modifying particles 186 throughout feedstock line 100,including into the shadows of elongate filaments 104.

Referring generally to, e.g., FIGS. 15-17, according to method 300, eachof optical direction-modifying particles 186 has a maximum outerdimension that is less than 1000 nm, 500 nm, 250 nm, or 200 nm. Thepreceding subject matter of this paragraph characterizes example 80 ofthe present disclosure, wherein example 80 also includes the subjectmatter according to example 78 or 79, above.

As discussed, typical reinforcement fibers for composite materials oftenhave a diameter in the range of 5 to 8 microns. By having a maximumouter dimension that is less than 1000 nm (1 micron), 500 nm (0.5micron), 250 nm (0.25 micron), or 200 nm (0.200 micron), opticaldirection-modifying particles 186 easily extend between typical sizes ofelongate filaments 104. Moreover, optical direction-modifying particles186 may easily flow with resin 124 to operatively disperse opticaldirection-modifying particles 186 throughout feedstock line 100,including into the shadows of elongate filaments 104.

Referring generally to, e.g., FIGS. 15-17, according to method 300,electromagnetic radiation 118 has a wavelength. Each of opticaldirection-modifying particles 186 has a minimum outer dimension that isgreater than one-fourth the wavelength of electromagnetic radiation 118.The preceding subject matter of this paragraph characterizes example 81of the present disclosure, wherein example 81 also includes the subjectmatter according to any one of examples 78 to 80, above.

Again, selecting a minimum outer dimension of opticaldirection-modifying particles 186 that is greater than one-fourth thewavelength of electromagnetic radiation 118 that will be used whenadditively manufacturing object 136 ensures that opticaldirection-modifying particles 186 will have the intended effect ofcausing electromagnetic radiation 118 to reflect, refract, or diffractupon hitting optical direction-modifying particles 186.

Referring generally to, e.g., FIGS. 15-17, according to method 300, eachof optical direction-modifying particles 186 has a minimum outerdimension that is greater than or equal to 50 nm or that is greater thanor equal to 100 nm. The preceding subject matter of this paragraphcharacterizes example 82 of the present disclosure, wherein example 82also includes the subject matter according to any one of examples 78 to81, above.

As discussed, ultra-violet light having a wavelength of about 400 nm isoften used in connection with ultra-violet photopolymers. Accordingly,when resin 124 comprises or consists of a photopolymer, opticaldirection-modifying particles 186 having a minimum outer dimension thatis greater than or equal to 100 nm ensures that opticaldirection-modifying particles 186 will have the intended effect ofcausing electromagnetic radiation 118 to reflect, refract, or diffractupon hitting optical direction-modifying particles 186. However, inother examples, a minimum outer dimension as low as 50 nm may beappropriate.

Referring generally to, e.g., FIGS. 1, 4, 6, and 7, according to method300, in feedstock line 100, optical direction-modifying particles 186comprise less than 10% by weight of resin 124, less than 5% by weight ofresin 124, or less than 1% by weight of resin 124. The preceding subjectmatter of this paragraph characterizes example 83 of the presentdisclosure, wherein example 83 also includes the subject matteraccording to any one of examples 78 to 82, above.

As discussed, by limiting optical direction-modifying particles 186 tothe referenced threshold percentages, resin 124 will operatively flowamong elongate filaments 104 when elongate filaments 104 and opticaldirection-modifying particles 186 are being combined to create feedstockline 100. In addition, desired properties of resin 124, feedstock line100, and ultimately object 136 will not be negatively impacted by thepresence of optical direction-modifying particles 186.

Referring generally to, e.g., FIGS. 15-17, according to method 300,outer surfaces 184 of at least some of optical direction-modifyingparticles 186 are faceted. The preceding subject matter of thisparagraph characterizes example 84 of the present disclosure, whereinexample 84 also includes the subject matter according to any one ofexamples 78 to 83, above.

Again, by being faceted, outer surfaces 184 effectively scatterelectromagnetic radiation 118.

Referring generally to, e.g., FIGS. 15-17, according to method 300,outer surfaces 184 of at least some of optical direction-modifyingparticles 186 have a surface roughness that is selected such that whenelectromagnetic radiation 118 strikes outer surfaces 184,electromagnetic radiation 118 is scattered. The preceding subject matterof this paragraph characterizes example 85 of the present disclosure,wherein example 85 also includes the subject matter according to any oneof examples 78 to 84, above.

As discussed, having a surface roughness selected to scatterelectromagnetic radiation 118 facilitates the operative irradiation ofresin 124 throughout feedstock line 100, including into the shadows ofelongate filaments 104, when feedstock line 100 is being used toadditively manufacture object 136.

Referring generally to, e.g., FIGS. 4, 6, and 7, according to method300, resin 124 has a resin refractive index. At least some of opticaldirection-modifying particles 186 have a particle refractive index. Theparticle refractive index is greater than or less than the resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 86 of the present disclosure, wherein example 86also includes the subject matter according to any one of examples 78 to85, above.

Again, when optical direction-modifying particles 186 have a refractiveindex that is different from the refractive index of resin 124,electromagnetic radiation 118 incident upon the outer surfaces thereofwill necessarily leave the outer surfaces at a different angle, and thuswill scatter throughout resin 124, including into the shadows ofelongate filaments 104.

Referring generally to, e.g., FIG. 15, according to method 300, at leastsome of optical direction-modifying particles 186 are spherical. Thepreceding subject matter of this paragraph characterizes example 87 ofthe present disclosure, wherein example 87 also includes the subjectmatter according to any one of examples 78 to 86, above.

Again, by being spherical, optical direction-modifying particles 186easily be positioned among elongate filaments 104 and may easily flowwith resin 124 as elongate filaments 104 and optical direction-modifyingparticles 186 are being combined.

Referring generally to, e.g., FIG. 16, according to method 300, at leastsome of optical direction-modifying particles 186 are prismatic. Thepreceding subject matter of this paragraph characterizes example 88 ofthe present disclosure, wherein example 88 also includes the subjectmatter according to any one of examples 78 to 87, above.

Again, by being prismatic, optical direction-modifying particles 186 maybe selected to operatively at least one of reflect, refract, or diffractelectromagnetic radiation 118, as discussed herein.

Referring generally to, e.g., FIGS. 13 and 14, and particularly to FIG.18, method 300 further comprises a step of (block 316) applyingadditional resin 125 to cover elongate filaments 104 and opticaldirection modifiers 123, such that elongate filaments 104 and opticaldirection modifiers 123 are covered by resin 124 and additional resin125 in derivative prepreg tow 209. The preceding subject matter of thisparagraph characterizes example 89 of the present disclosure, whereinexample 89 also includes the subject matter according to any one ofexamples 69 to 88, above.

As discussed in connection with system 200, applying additional resin125 to elongate filaments 104 and optical direction modifiers 123ensures full wet-out of elongate filaments 104 and optical directionmodifiers 123 in feedstock line 100.

Referring generally to, e.g., FIGS. 13 and 14, and particularly to FIG.18, according to method 300, additional resin 125 is applied to coverelongate filaments 104 and optical direction modifiers 123, such thatelongate filaments 104 and optical direction modifiers 123 are coveredby resin 124 and additional resin 125 in derivative prepreg tow 209, atleast one of before or after (block 302) separating precursor prepregtow 208 into the individual ones of elongate filaments 104, at leastpartially covered with resin 124, or into subsets 214 of elongatefilaments 104, at least partially covered with resin 124. The precedingsubject matter of this paragraph characterizes example 90 of the presentdisclosure, wherein example 90 also includes the subject matteraccording to example 89, above.

In some implementations of method 300, applying additional resin 125before precursor prepreg tow 208 is separated enables a correspondingsystem (e.g., system 200 herein) to regulate the amount of additionalresin 125 on each individual one of elongate filaments 104 or subset 214of elongate filaments 104. For example, when a screen or mesh is used toseparate precursor prepreg tow 208, the screen or mesh may effectivelyscrape away excess additional resin 125 leaving only a desired amount oneach individual one of elongate filaments 104 or subset 214 of elongatefilaments 104.

On the other hand, in some implementations of method 300, applyingadditional resin 125 after precursor prepreg tow 208 is separatedenables a sufficient amount of additional resin 125 to fully wetelongate filaments 104 and optical direction modifiers 123.

In some implementations of method 300, additional resin 125 may beapplied both before and after precursor prepreg tow 208 is separated.

Referring generally to, e.g., FIGS. 13 and 14, and particularly to FIG.18, according to method 300, additional resin 125 is applied to coverelongate filaments 104 and optical direction modifiers 123, such thatelongate filaments 104 and optical direction modifiers 123 are coveredby resin 124 and additional resin 125 in derivative prepreg tow 209, atleast one of before or after (block 306) combining optical directionmodifiers 123 with the individual ones of elongate filaments 104, atleast partially covered with resin 124, or subsets 214 of elongatefilaments 104, at least partially covered with resin 124, intoderivative prepreg tow 209. The preceding subject matter of thisparagraph characterizes example 91 of the present disclosure, whereinexample 91 also includes the subject matter according to example 89 or90, above.

In some implementations of method 300, applying additional resin 125before elongate filaments 104 and optical direction modifiers 123 arecombined enables a sufficient amount of resin 124 and additional resin125 to fully wet elongate filaments 104 and optical direction modifiers123.

In some implementations of method 300, applying additional resin 125after elongate filaments 104 and optical direction modifiers 123 arecombined into derivative prepreg tow 209 ensures that feedstock line 100has the overall desired amount of resin 124 and additional resin 125therein.

In some implementations of method 300, additional resin 125 may beapplied both before and after elongate filaments 104 and opticaldirection modifiers 123 are combined.

Referring generally to, e.g., FIGS. 13 and 14, and particularly to FIG.18, according to method 300, the step of (block 302) separatingprecursor prepreg tow 208 into individual ones of elongate filaments104, at least partially covered with resin 124, or into subsets 214 ofelongate filaments 104, at least partially covered with resin 124,comprises (block 318) imparting a first electrical charge to elongatefilaments 104 or resin 124. Also according to method 300, the step of(block 316) applying additional resin 125 to cover elongate filaments104 and optical direction modifiers 123, such that elongate filaments104 and optical direction modifiers 123 are covered by resin 124 andadditional resin 125 in derivative prepreg tow 209, comprises (block320) imparting a second electrical charge to additional resin 125. Thesecond electrical charge and the first electrical charge have oppositesigns. The preceding subject matter of this paragraph characterizesexample 92 of the present disclosure, wherein example 92 also includesthe subject matter according to any one of examples 89 to 91, above.

As discussed in connection with system 200, by imparting a firstelectrical charge to elongate filaments 104 or resin 124 and byimparting a second opposite charge to additional resin 125 as it isapplied to elongate filaments 104 and resin 124, additional resin 125will be electrostatically attracted to elongate filaments 104, therebyfacilitating wetting of elongate filaments 104 with additional resin125.

Referring generally to, e.g., FIGS. 13 and 14, and particularly to FIG.18, according to method 300, the step of (block 306) combining opticaldirection modifiers 123 with the individual ones of elongate filaments104, at least partially covered with resin 124, or subsets 214 ofelongate filaments 104, at least partially covered with resin 124, intoderivative prepreg tow 209 comprises (block 322) combining at least onefull-length optical waveguide 102, optical direction modifiers 123, andthe individual ones of elongate filaments 104, at least partiallycovered with resin 124, or subsets 214 of elongate filaments 104, atleast partially covered with resin 124, into derivative prepreg tow 209so that each of elongate filaments 104 and at least one full-lengthoptical waveguide 102 extends along all of the feedstock-line length andat least one full-length optical waveguide 102 is interspersed amongelongate filaments 104. The preceding subject matter of this paragraphcharacterizes example 93 of the present disclosure, wherein example 93also includes the subject matter according to any one of examples 69 to92, above.

As discussed, inclusion of at least one full-length optical waveguide102 in feedstock line 100 further facilitates penetration ofelectromagnetic radiation 118 into interior volume 182 of feedstock line100 for irradiation of resin 124, despite regions of resin 124 being inthe shadows of elongate filaments 104 cast by the direct (i.e.,line-of-sight) application of electromagnetic radiation 118.

Referring generally to, e.g., FIGS. 2 and 9-12, according to method 300,at least one full-length optical waveguide 102 comprises full-lengthoptical core 110. Full-length optical core 110 comprises firstfull-length-optical-core end face 112, second full-length-optical-coreend face 114, opposite first full-length-optical-core end face 112, andfull-length peripheral surface 116, extending between firstfull-length-optical-core end face 112 and secondfull-length-optical-core end face 114. At least one full-length opticalwaveguide 102 is configured such that when electromagnetic radiation 118enters full-length optical core 110 via at least one of firstfull-length-optical-core end face 112, second full-length-optical-coreend face 114, or full-length peripheral surface 116, at least a portionof electromagnetic radiation 118 exits full-length optical core 110 viafull-length peripheral surface 116. The preceding subject matter of thisparagraph characterizes example 94 of the present disclosure, whereinexample 94 also includes the subject matter according to example 93,above.

Again, when feedstock line 100 is used to additively manufacture object136 with in situ curing thereof (i.e., with electromagnetic radiation118 entering full-length optical core 110), at least a portion ofelectromagnetic radiation 118 will be emitted from full-length opticalcore 110 at a position that is spaced-apart from where it enteredfull-length optical core 110. As a result, electromagnetic radiation maybe dispersed throughout interior volume 182 of feedstock line 100 foroperative irradiation of resin 124.

Referring generally to, e.g., FIGS. 2 and 9-12, according to method 300,at least one full-length optical waveguide 102 is configured such thatwhen electromagnetic radiation 118 enters first full-length-optical-coreend face 112 of full-length optical core 110, an initial portion ofelectromagnetic radiation 118 exits full-length optical core 110 viafull-length peripheral surface 116 and a final portion ofelectromagnetic radiation 118, remaining in full-length optical core 110after the initial portion of electromagnetic radiation 118 exitsfull-length optical core 110, exits full-length optical core 110 viasecond full-length-optical-core end face 114. The preceding subjectmatter of this paragraph characterizes example 95 of the presentdisclosure, wherein example 95 also includes the subject matteraccording to example 94, above.

As discussed, in some examples of feedstock line 100, if electromagneticradiation 118 enters first full-length-optical-core end face 112, itwill exit both full-length peripheral surface 116 and secondfull-length-optical-core end face 114, as opposed, for example, toelectromagnetic radiation 118 being fully emitted via full-lengthperipheral surface 116. Such examples of feedstock line 100 are wellsuited for additive manufacturing systems and methods in whichelectromagnetic radiation 118 is directed at firstfull-length-optical-core end face 112 as feedstock line 100 is beingconstructed and as object 136 is being manufactured.

Referring generally to, e.g., FIGS. 2 and 9-12, according to method 300,at least one full-length optical waveguide 102 is configured such thatthe initial portion of electromagnetic radiation 118, which exitsfull-length optical core 110 via full-length peripheral surface 116, isgreater than or equal to the final portion of electromagnetic radiation118, which exits full-length optical core 110 via secondfull-length-optical-core end face 114. The preceding subject matter ofthis paragraph characterizes example 96 of the present disclosure,wherein example 96 also includes the subject matter according to example95, above.

Again, in such configurations of at least one full-length opticalwaveguide 102, it is ensured that a desired amount of electromagneticradiation 118 exits full-length optical core 110 via full-lengthperipheral surface 116 to operatively cure resin 124 among elongatefilaments 104 within interior volume 182 of feedstock line 100 whenfeedstock line 100 is used to additively manufacture object 136.

Referring generally to, e.g., FIGS. 2 and 9-11, according to method 300,full-length optical core 110 has a full-length-optical-core refractiveindex. At least one full-length optical waveguide 102 further comprisesfull-length-optical-core cladding 154, at least partially coveringfull-length optical core 110. Full-length-optical-core cladding 154comprises at least first full-length-optical-core cladding resin 156,having a full-length-optical-core first-cladding-resin refractive index.Full-length-optical-core cladding 154 is non-uniform along at least onefull-length optical waveguide 102. The full-length-optical-corerefractive index is greater than the full-length-optical-corefirst-cladding-resin refractive index. The preceding subject matter ofthis paragraph characterizes example 97 of the present disclosure,wherein example 97 also includes the subject matter according to any oneof examples 94 to 96, above.

Again, by full-length-optical-core cladding 154 being non-uniform alongthe length of at least one full-length optical waveguide 102,electromagnetic radiation 118 is permitted to exit full-length opticalcore 110 via full-length peripheral surface 116. Moreover, by firstfull-length-optical-core cladding resin 156 having a refractive indexthat is less than that of full-length optical core 110, electromagneticradiation 118, upon entering full-length optical core 110, is trappedwithin full-length optical core 110 other than the regions where firstfull-length-optical-core cladding resin 156 is not present. As a result,at least one full-length optical waveguide 102 may be constructed toprovide a desired amount of electromagnetic radiation 118, exitingvarious positions along full-length peripheral surface 116, such as toensure a desired amount of electromagnetic radiation 118, penetratingthe shadows of elongate filaments 104 when feedstock line 100 is used toadditively manufacture object 136.

Referring generally to, e.g., FIGS. 2, 10, and 11, according to method300, full-length peripheral surface 116 hasfull-length-peripheral-surface regions 127 devoid of firstfull-length-optical-core cladding resin 156. Full-length-optical-corecladding 154 further comprises second full-length-optical-core claddingresin 158, having a full-length-optical-core second-cladding-resinrefractive index. Second full-length-optical-core cladding resin 158covers full-length-peripheral-surface regions 127 of full-lengthperipheral surface 116. The full-length-optical-coresecond-cladding-resin refractive index is greater than thefull-length-optical-core first-cladding-resin refractive index. Thepreceding subject matter of this paragraph characterizes example 98 ofthe present disclosure, wherein example 98 also includes the subjectmatter according to example 97, above.

Again, by covering full-length-peripheral-surface regions 127 withsecond full-length-optical-core cladding resin 158, a desired refractiveindex thereof may be selected to optimize how electromagnetic radiation118 exits full-length peripheral surface 116. Additionally oralternatively, with full-length-peripheral-surface regions 127 coveredwith second full-length-optical-core cladding resin 158, the integrityof first full-length-optical-core cladding resin 156 may be ensured,such that it does not peel or break off during storage of at least onefull-length optical waveguide 102 and during implementation of method300.

Referring generally to, e.g., FIGS. 2 and 11, according to method 300,second full-length-optical-core cladding resin 158 also covers firstfull-length-optical-core cladding resin 156. The preceding subjectmatter of this paragraph characterizes example 99 of the presentdisclosure, wherein example 99 also includes the subject matteraccording to example 98, above.

As discussed, full-length optical waveguides, such as according toexample 99, may be more easily manufactured, in that full-length opticalcore 110 with first full-length-optical-core cladding resin 156 simplymay be fully coated with second full-length-optical-core cladding resin158. Additionally or alternatively, the integrity of full-length opticalwaveguides may be maintained during storage thereof and duringimplementation of method 300.

Referring generally to, e.g., FIGS. 2, 10, and 11, according to method300, resin 124 has a resin refractive index. The resin refractive indexis greater than the full-length-optical-core second-cladding-resinrefractive index. The preceding subject matter of this paragraphcharacterizes example 100 of the present disclosure, wherein example 100also includes the subject matter according to example 98 or 99, above.

As discussed, because second full-length-optical-core cladding resin 158has a refractive index less than that of resin 124, electromagneticradiation 118 will be permitted to exit second full-length-optical-corecladding resin 158 to penetrate and cure resin 124 when feedstock line100 is used to additively manufacture object 136.

Referring generally to, e.g., FIGS. 2 and 12, according to method 300,full-length peripheral surface 116 has a surface roughness that isselected such that when electromagnetic radiation 118 enters full-lengthoptical core 110 via at least one of first full-length-optical-core endface 112, second full-length-optical-core end face 114, or full-lengthperipheral surface 116, at least a portion of electromagnetic radiation118 exits full-length optical core 110 via full-length peripheralsurface 116. The preceding subject matter of this paragraphcharacterizes example 101 of the present disclosure, wherein example 101also includes the subject matter according to any one of examples 94 to96, above.

As discussed, rather than relying on refractive-index properties of acladding to ensure desired dispersal of electromagnetic radiation 118from full-length optical core 110 via full-length peripheral surface116, the surface roughness of full-length peripheral surface 116 isselected such that electromagnetic radiation 118 exits full-lengthoptical core 110 at desired amounts along the length of full-lengthperipheral surface 116. For example, the surface roughness may createregions of internal reflection of electromagnetic radiation 118 withinfull-length optical core 110 and may create regions whereelectromagnetic radiation 118 is permitted to escape full-length opticalcore 110.

Referring generally to, e.g., FIGS. 2 and 12, according to method 300,at least one full-length optical waveguide 102 is devoid of any claddingthat covers full-length optical core 110. The preceding subject matterof this paragraph characterizes example 102 of the present disclosure,wherein example 102 also includes the subject matter according toexample 101, above.

As discussed, full-length optical waveguides without any cladding may beless expensive to manufacture than full-length optical waveguides withcladding. Additionally, the difference of refractive indexes between acladding and resin 124 need not be taken into account when selectingresin 124 for feedstock line 100.

Referring generally to, e.g., FIG. 14, and particularly to FIG. 18,according to method 300, the step of (block 322) combining at least onefull-length optical waveguide 102, optical direction modifiers 123, andthe individual ones of elongate filaments 104, at least partiallycovered with resin 124, or subsets 214 of elongate filaments 104, atleast partially covered with resin 124, into derivative prepreg tow 209comprises (block 324) at least one of twisting, weaving, or braiding atleast one full-length optical waveguide 102 and individual ones ofelongate filaments 104, at least partially covered with resin 124, orsubsets 214 of elongate filaments 104, at least partially covered withresin 124, into derivative prepreg tow 209. The preceding subject matterof this paragraph characterizes example 103 of the present disclosure,wherein example 103 also includes the subject matter according to anyone of examples 93 to 102, above.

Again, by being twisted with, woven with, or braided with elongatefilaments 104, at least one full-length optical waveguide 102 isinterspersed with elongate filaments 104 so that electromagneticradiation 118, exiting at least one full-length optical waveguide 102,is delivered to regions of interior volume 182 that are in the shadowsof elongated filaments 104 when feedstock line 100 is used to additivelymanufacture object 136.

Referring generally to FIG. 3 and particularly to, e.g., FIGS. 9-12,optical waveguide 108 is disclosed. Optical waveguide 108 comprisesoptical core 146, comprising first end face 148, second end face 150,opposite first end face 148, and peripheral surface 152, extendingbetween first end face 148 and second end face 150. Optical waveguide108 is configured such that when electromagnetic radiation 118 entersoptical core 146 via at least one of first end face 148, second end face150, or peripheral surface 152, at least a portion of electromagneticradiation 118 exits optical core 146 via peripheral surface 152. Thepreceding subject matter of this paragraph characterizes example 104 ofthe present disclosure.

Because optical waveguide 108 is configured for electromagneticradiation to enter optical core 146 via any one of first end face 148,second end face 150, or peripheral surface 152 and then exit opticalcore 146 via peripheral surface 152, optical waveguide 108 is wellsuited for inclusion in a photopolymer resin (e.g., resin 124 herein) ofa feedstock line (e.g., feedstock line 100 here) that also includesreinforcing fibers (e.g., elongate filaments 104 herein) and that isused to additively manufacture an object (e.g., object 136 herein). Morespecifically, inclusion of at least one optical waveguide 108 in such afeedstock line facilitates penetration of electromagnetic radiation 118into the interior volume of the feedstock line for irradiation of theresin, despite regions of the resin being in the shadows of thereinforcing fibers cast by the direct (i.e., line-of-sight) applicationof electromagnetic radiation 118. In other words, even whenelectromagnetic radiation 118 is shielded from directly reaching allregions of the resin, at least one optical waveguide 108 will receiveelectromagnetic radiation 118 via one or more of first end face 148,second end face 150, or peripheral surface 152, and disperseelectromagnetic radiation 118 via at least peripheral surface 152 toindirectly reach regions of the resin. As a result, the feedstock linemay be more easily cured with electromagnetic radiation 118, may be moreevenly cured with electromagnetic radiation 118, may be more thoroughlycured with electromagnetic radiation 118, and/or may be more quicklycured with electromagnetic radiation 118. Such a configuration offeedstock line is particularly well suited for additive manufacturing ofthe fused filament fabrication variety, in which the feedstock line isdispensed by a print head, or nozzle, and a source of curing energy(e.g., electromagnetic radiation 118) directs the curing energy at thefeedstock line as it is being dispensed to cure the resin in situ.

Full-length optical waveguides and partial-length optical waveguides areexamples of optical waveguides, such as optical waveguide 108.

Referring generally to FIG. 3 and particularly to, e.g., FIGS. 9-12,optical waveguide 108 is configured such that when electromagneticradiation 118 enters first end face 148 of optical core 146, an initialportion of electromagnetic radiation 118 exits optical core 146 viaperipheral surface 152 and a final portion of electromagnetic radiation118, remaining in optical core 146 after the initial portion ofelectromagnetic radiation 118 exits optical core 146, exits optical core146 via second end face 150. The preceding subject matter of thisparagraph characterizes example 105 of the present disclosure, whereinexample 105 also includes the subject matter according to example 104,above.

That is, when electromagnetic radiation 118 enters first end face 148,it will exit both peripheral surface 152 and second end face 150, asopposed, for example, to electromagnetic radiation 118 being fullyemitted via peripheral surface 152. Such examples of optical waveguide108 are well suited for inclusion in feedstock lines with additivemanufacturing systems and methods in which electromagnetic radiation 118is directed at first end face 148 as the feedstock line is beingconstructed and as an object is being manufactured. That is, an additivemanufacturing system may be configured to construct a feedstock linewhile the object is being manufactured from the feedstock line, andwhile electromagnetic radiation 118 is entering first end face 148.Because electromagnetic radiation 118 exits not only peripheral surface152, but also second end face 150, it is ensured that sufficientelectromagnetic radiation 118 travels the full length of opticalwaveguide 108 to operatively cure the resin of the feedstock line thatis in the shadows of the reinforcing fibers.

Referring generally to FIG. 3 and particularly to, e.g., FIGS. 9-12,optical waveguide 108 is configured such that the initial portion ofelectromagnetic radiation 118, which exits optical core 146 viaperipheral surface 152, is greater than or equal to the final portion ofelectromagnetic radiation 118, which exits optical core 146 via secondend face 150. The preceding subject matter of this paragraphcharacterizes example 106 of the present disclosure, wherein example 106also includes the subject matter according to example 105, above.

In such configurations, it is ensured that a desired amount ofelectromagnetic radiation 118 exits optical core 146 via peripheralsurface 152 to operatively cure the resin of a feedstock line that is inthe shadows of the reinforcing fibers, when the feedstock line isutilized by an additive manufacturing system or in an additivemanufacturing method.

Referring generally to FIG. 3 and particularly to, e.g., FIGS. 9-11,optical core 146 has an optical-core refractive index. Optical waveguide108 further comprises cladding 120, at least partially covering opticalcore 146. Cladding 120 comprises at least first resin 132, having afirst-resin refractive index. Cladding 120 is non-uniform along opticalwaveguide 108. The optical-core refractive index is greater than thefirst-resin refractive index. The preceding subject matter of thisparagraph characterizes example 107 of the present disclosure, whereinexample 107 also includes the subject matter according to any one ofexamples 104 to 106, above.

By cladding 120 being non-uniform along the length of optical waveguide108, electromagnetic radiation 118 is permitted to exit optical core 146via peripheral surface 152. Moreover, by first resin 132 having arefractive index that is less than that of optical core 146,electromagnetic radiation 118, upon entering optical core 146, istrapped within optical core 146 other than the regions where first resin132 is not present. As a result, optical waveguide 108 may beconstructed to provide a desired amount of electromagnetic radiation118, exiting various positions along peripheral surface 152, such as toensure a desired amount of electromagnetic radiation 118, penetratingthe shadows of reinforcing fibers when optical waveguide 108 is includedin a feedstock line that is used to additively manufacture an object.

Referring generally to FIG. 3 and particularly to, e.g., FIGS. 10 and11, peripheral surface 152 has regions 130 devoid of first resin 132.Cladding 120 further comprises second resin 134, having a second-resinrefractive index. Second resin 134 contacts regions 130 of peripheralsurface 152. The second-resin refractive index is greater than thefirst-resin refractive index. The preceding subject matter of thisparagraph characterizes example 108 of the present disclosure, whereinexample 108 also includes the subject matter according to example 107,above.

By covering regions 130 with second resin 134, a desired refractiveindex thereof may be selected to optimize how electromagnetic radiation118 exits peripheral surface 152. Additionally or alternatively, withregions 130 covered with second resin 134, the integrity of first resin132 may be ensured, such that it does not peel or break off duringstorage of optical waveguide 108 and during construction of anassociated feedstock line.

Referring generally to FIG. 3 and particularly to, e.g., FIG. 11, secondresin 134 covers first resin 132. The preceding subject matter of thisparagraph characterizes example 109 of the present disclosure, whereinexample 109 also includes the subject matter according to example 108,above.

Optical waveguides, such as optical waveguide 108, may be more easilymanufactured, in that optical core 146 with first resin 132 simply maybe fully coated with second resin 134. Additionally or alternatively,the integrity of optical waveguides may be maintained during storagethereof and during construction of an associated feedstock line.

Referring generally to FIG. 3 and particularly to, e.g., FIG. 12,peripheral surface 152 has a surface roughness that is selected suchthat when electromagnetic radiation 118 enters optical core 146 via atleast one of first end face 148, second end face 150, or peripheralsurface 152, at least a portion of electromagnetic radiation 118 exitsoptical core 146 via peripheral surface 152. The preceding subjectmatter of this paragraph characterizes example 110 of the presentdisclosure, wherein example 110 also includes the subject matteraccording to any one of examples 104 to 106, above.

Rather than relying on refractive index properties of a cladding toensure desired dispersal of electromagnetic radiation 118 from opticalcore 146 via peripheral surface 152, the surface roughness of peripheralsurface 152 is selected such that electromagnetic radiation 118 exitsoptical core 146 at desired amounts along the length of peripheralsurface 152. For example, the surface roughness may create regions ofinternal reflection of electromagnetic radiation 118 within optical core146 and may create regions where electromagnetic radiation 118 ispermitted to escape optical core 146.

Referring generally to FIG. 3 and particularly to, e.g., FIG. 12,optical waveguide 108 is devoid of any cladding that covers optical core146. The preceding subject matter of this paragraph characterizesexample 111 of the present disclosure, wherein example 111 also includesthe subject matter according to example 110, above.

Optical waveguides without any cladding may be less expensive tomanufacture than optical waveguides with cladding. Additionally, thedifference of refractive indexes between a cladding and a resin of afeedstock line need not be taken into account when selecting the resinfor the feedstock line.

Referring generally to, e.g., FIGS. 3,8, and 9, and particularly to FIG.19, method 400 of modifying optical fiber 126 to create opticalwaveguide 108 is disclosed. Optical fiber 126 comprises optical core146, having an optical-core refractive index, and cladding 120,comprising at least first resin 132, having a first-resin refractiveindex that is less than the optical-core refractive index. Cladding 120covers peripheral surface 152 of optical core 146 and extends betweenfirst end face 148 and second end face 150 of optical core 146. Method400 comprises a step of (block 402) removing portions 128 of cladding120 to expose regions 130 of peripheral surface 152, such that at leasta portion of electromagnetic radiation 118, entering optical core 146via at least one of first end face 148, second end face 150, orperipheral surface 152, exits optical core 146 via regions 130 ofperipheral surface 152. The preceding subject matter of this paragraphcharacterizes example 112 of the present disclosure.

Method 400 provides an inexpensive process for creating opticalwaveguide 108. For example, an off-the-shelf cladded optical fiber maybe used as optical fiber 126, and portions 128 of cladding 120 simplymay be removed at regions 130 that are appropriately spaced apart toresult in the desired functions of optical waveguide 108, discussedherein.

Any suitable process may be utilized to remove portion 128 of cladding120, including, for example, mechanical processes, chemical processes,thermal processes (e.g., utilizing a laser), etc.

Referring generally to, e.g., FIGS. 3 and 8-11, and particularly to FIG.19, method 400 further comprises a step of (block 404) applying secondresin 134 to contact regions 130 of peripheral surface 152. Second resin134 has a second-resin refractive index that is greater than thefirst-resin refractive index. The preceding subject matter of thisparagraph characterizes example 113 of the present disclosure, whereinexample 113 also includes the subject matter according to example 112,above.

As discussed, by covering regions 130 with second resin 134, a desiredrefractive index thereof may be selected to optimize how electromagneticradiation 118 exits peripheral surface 152. Additionally oralternatively, with regions 130 covered with second resin 134, theintegrity of first resin 132 may be ensured, such that it does not peelor break off during storage of optical waveguide 108 and duringconstruction of an associated feedstock line.

Referring generally to, e.g., FIGS. 3, 8, 9, and 11, and particularly toFIG. 19, according to method 400, the step of (block 404) applyingsecond resin 134 to contact regions 130 of peripheral surface 152comprises (block 406) covering first resin 132 with second resin 134.The preceding subject matter of this paragraph characterizes example 114of the present disclosure, wherein example 114 also includes the subjectmatter according to example 113, above.

Applying second resin 134 such that it also covers first resin 132 maybe an easier and less-expensive process than applying second resin 134only to contact and cover regions 130.

Referring generally to, e.g., FIGS. 3 and 9, and particularly to FIG.20, method 500 of modifying optical core 146 to create optical waveguide108 is disclosed. Optical core 146 comprises first end face 148, secondend face 150, opposite first end face 148, and peripheral surface 152,extending between first end face 148 and second end face 150. Method 500comprises a step of (block 502) applying first resin 132 to peripheralsurface 152 of optical core 146 so that regions 130 of peripheralsurface 152 remain uncovered by first resin 132. First resin 132 has afirst-resin refractive index. Optical core 146 has an optical-corerefractive index that is greater than the first-resin refractive index.At least a portion of electromagnetic radiation 118, entering opticalcore 146 via at least one of first end face 148, second end face 150, orperipheral surface 152, exits optical core 146 via peripheral surface152. The preceding subject matter of this paragraph characterizesexample 115 of the present disclosure.

Method 500 provides an inexpensive process for creating opticalwaveguide 108. For example, an off-the-shelf non-cladded optical fibermay be used as optical core 146, and first resin 132 may be applied toperipheral surface 152 thereof.

Any suitable process for applying first resin 132 may be used,including, for example spraying, misting, or splattering first resin 132on peripheral surface 152, such that regions 130 of peripheral surface152 remain uncovered by first resin 132.

Referring generally to, e.g., FIGS. 3 and 9-11, and particularly to FIG.20, method 500 further comprises a step of (block 504) applying secondresin 134 to contact regions 130 of peripheral surface 152 to createwith first resin 132 cladding 120 that covers peripheral surface 152 ofoptical core 146. Second resin 134 has a second-resin refractive indexthat is greater than the first-resin refractive index. The precedingsubject matter of this paragraph characterizes example 116 of thepresent disclosure, wherein example 116 also includes the subject matteraccording to example 115, above.

Similar to method 400, by covering regions 130 with second resin 134, adesired refractive index thereof may be selected to optimize howelectromagnetic radiation 118 exits peripheral surface 152. Additionallyor alternatively, with regions 130 covered with second resin 134, theintegrity of first resin 132 may be ensured, such that it does not peelor break off during storage of optical waveguide 108 and duringconstruction of an associated feedstock line.

Referring generally to, e.g., FIGS. 3, 9, and 11, and particularly toFIG. 20, according to method 500, the step of (block 504) applyingsecond resin 134 to contact regions 130 of peripheral surface 152comprises (block 506) covering first resin 132 with second resin 134.The preceding subject matter of this paragraph characterizes example 117of the present disclosure, wherein example 117 also includes the subjectmatter according to example 116, above.

Again, applying second resin 134 such that it also covers first resin132 may be an easier and less-expensive process than applying secondresin 134 only to contact and cover regions 130.

Referring generally to, e.g., FIGS. 3 and 12, and particularly to FIG.21, method 600 of modifying optical core 146 to create optical waveguide108 is disclosed. Optical core 146 comprises first end face 148, secondend face 150, opposite first end face 148, and peripheral surface 152,extending between first end face 148 and second end face 150. Method 600comprises a step of (block 602) increasing surface roughness of all orportions of peripheral surface 152 of optical core 146 so that at leasta portion of electromagnetic radiation 118, entering optical core 146via at least one of first end face 148, second end face 150, orperipheral surface 152, exits optical core 146 via peripheral surface152. The preceding subject matter of this paragraph characterizesexample 118 of the present disclosure.

Method 600 provides an inexpensive process for creating opticalwaveguide 108. For example, an off-the-shelf non-cladded optical fibermay be used as optical core 146, and peripheral surface 152 thereof maybe roughened.

Any suitable process for increasing surface roughness of peripheralsurface may be used including, for example, mechanical processes,chemical processes, thermal processes (e.g., utilizing a laser), etc.

Referring generally to, e.g., FIGS. 3 and 12, and particularly to FIG.21, method 600 further comprises (block 604) applying cladding 120 tocover peripheral surface 152. Optical core 146 has an optical-corerefractive index. Cladding 120 has a cladding refractive index. Theoptical-core refractive index is less than the cladding refractiveindex. The preceding subject matter of this paragraph characterizesexample 119 of the present disclosure, wherein example 119 also includesthe subject matter according to example 118, above.

By applying cladding 120 to cover peripheral surface 152, the integrityof the surface roughness of peripheral surface 152 may be maintained,and by selecting a cladding refractive index that is less than theoptical-core refractive index ensures that electromagnetic radiation 118can operatively exit optical core 146 at desired locations as a resultof the surface roughness of peripheral surface 152.

Examples of the present disclosure may be described in the context ofaircraft manufacturing and service method 1100 as shown in FIG. 22 andaircraft 1102 as shown in FIG. 23. During pre-production, illustrativemethod 1100 may include specification and design (block 1104) ofaircraft 1102 and material procurement (block 1106). During production,component and subassembly manufacturing (block 1108) and systemintegration (block 1110) of aircraft 1102 may take place. Thereafter,aircraft 1102 may go through certification and delivery (block 1112) tobe placed in service (block 1114). While in service, aircraft 1102 maybe scheduled for routine maintenance and service (block 1116). Routinemaintenance and service may include modification, reconfiguration,refurbishment, etc. of one or more systems of aircraft 1102.

Each of the processes of illustrative method 1100 may be performed orcarried out by a system integrator, a third party, and/or an operator(e.g., a customer). For the purposes of this description, a systemintegrator may include, without limitation, any number of aircraftmanufacturers and major-system subcontractors; a third party mayinclude, without limitation, any number of vendors, subcontractors, andsuppliers; and an operator may be an airline, leasing company, militaryentity, service organization, and so on.

As shown in FIG. 23, aircraft 1102 produced by illustrative method 1100may include airframe 1118 with a plurality of high-level systems 1120and interior 1122. Examples of high-level systems 1120 include one ormore of propulsion system 1124, electrical system 1126, hydraulic system1128, and environmental system 1130. Any number of other systems may beincluded. Although an aerospace example is shown, the principlesdisclosed herein may be applied to other industries, such as theautomotive industry. Accordingly, in addition to aircraft 1102, theprinciples disclosed herein may apply to other vehicles, e.g., landvehicles, marine vehicles, space vehicles, etc.

Apparatus(es) and method(s) shown or described herein may be employedduring any one or more of the stages of the manufacturing and servicemethod 1100. For example, components or subassemblies corresponding tocomponent and subassembly manufacturing (block 1108) may be fabricatedor manufactured in a manner similar to components or subassembliesproduced while aircraft 1102 is in service (block 1114). Also, one ormore examples of the apparatus(es), method(s), or combination thereofmay be utilized during production stages 1108 and 1110, for example, bysubstantially expediting assembly of or reducing the cost of aircraft1102. Similarly, one or more examples of the apparatus or methodrealizations, or a combination thereof, may be utilized, for example andwithout limitation, while aircraft 1102 is in service (block 1114)and/or during maintenance and service (block 1116).

Different examples of the apparatus(es) and method(s) disclosed hereininclude a variety of components, features, and functionalities. Itshould be understood that the various examples of the apparatus(es) andmethod(s) disclosed herein may include any of the components, features,and functionalities of any of the other examples of the apparatus(es)and method(s) disclosed herein in any combination, and all of suchpossibilities are intended to be within the scope of the presentdisclosure.

Many modifications of examples set forth herein will come to mind to oneskilled in the art to which the present disclosure pertains having thebenefit of the teachings presented in the foregoing descriptions and theassociated drawings. Therefore, it is to be understood that the presentdisclosure is not to be limited to the specific examples illustrated andthat modifications and other examples are intended to be included withinthe scope of the appended claims. Moreover, although the foregoingdescription and the associated drawings describe examples of the presentdisclosure in the context of certain illustrative combinations ofelements and/or functions, it should be appreciated that differentcombinations of elements and/or functions may be provided by alternativeimplementations without departing from the scope of the appended claims.Accordingly, parenthetical reference numerals in the appended claims arepresented for illustrative purposes only and are not intended to limitthe scope of the claimed subject matter to the specific examplesprovided in the present disclosure.

1-34. (canceled)
 35. A system for creating a feedstock line for additivemanufacturing of an object, the feedstock line having a feedstock-linelength, the system comprising: a prepreg-tow supply, configured todispense a precursor prepreg tow, comprising elongate filaments andresin, covering the elongate filaments; a prepreg-tow separator,configured to separate the precursor prepreg tow, dispensed from theprepreg-tow supply, into individual ones of the elongate filaments, atleast partially covered with the resin, or into subsets of the elongatefilaments, at least partially covered with the resin, wherein each ofthe subsets comprises a plurality of the elongate filaments; anoptical-direction-modifier supply, configured to dispense opticaldirection modifiers to be applied to the individual ones of the elongatefilaments, at least partially covered with the resin, or the subsets ofthe elongate filaments, at least partially covered by the resin,originating from the prepreg-tow separator, wherein each of the opticaldirection modifiers has an outer surface, and each of the opticaldirection modifiers is configured such that when electromagneticradiation strikes the outer surface from a first direction, at least aportion of the electromagnetic radiation departs the outer surface in asecond direction that is at an angle to the first direction; a combiner,configured to combine the individual ones of the elongate filaments, atleast partially covered with the resin, and the optical directionmodifiers, dispensed by the optical-direction-modifier supply, or tocombine the subsets of the elongate filaments, at least partiallycovered with the resin, and the optical direction modifiers, dispensedby the optical-direction-modifier supply, into a derivative prepreg towso that the optical direction modifiers are interspersed among theelongate filaments; and at least one heater, configured to heat at leastone of: the resin in the precursor prepreg tow, dispensed from theprepreg-tow supply, to a first threshold temperature to facilitateseparation of the precursor prepreg tow by the prepreg-tow separatorinto the individual ones of the elongate filaments or into the subsetsof the elongate filaments; the resin that at least partially covers theindividual ones of the elongate filaments or the subsets of the elongatefilaments, originating from the prepreg-tow separator, to a secondthreshold temperature to cause wet-out of the optical directionmodifiers and the elongate filaments in the derivative prepreg tow bythe resin; or the resin that at least partially covers the elongatefilaments in the derivative prepreg tow, originating from the combiner,to a third threshold temperature to cause wet-out of the opticaldirection modifiers and the elongate filaments in the derivative prepregtow by the resin.
 36. The system according to claim 35, wherein theelongate filaments are opaque to electromagnetic radiation.
 37. Thesystem according to claim 35, wherein: the optical direction modifierscomprise partial-length optical waveguides; each of the partial-lengthoptical waveguides comprises a partial-length optical core; thepartial-length optical core of each of the partial-length opticalwaveguides comprises a first partial-length-optical-core end face, asecond partial-length-optical-core end face, opposite the firstpartial-length-optical-core end face, and a partial-length peripheralsurface, extending between the first partial-length-optical-core endface and the second partial-length-optical-core end face; and each ofthe partial-length optical waveguides is configured such that when theelectromagnetic radiation enters the partial-length optical core via atleast one of the first partial-length-optical-core end face, the secondpartial-length-optical-core end face, or the partial-length peripheralsurface, at least a portion of the electromagnetic radiation exits thepartial-length optical core via the partial-length peripheral surface.38. The system according to claim 37, wherein: the partial-lengthoptical core has a partial-length-optical-core refractive index; each ofthe partial-length optical waveguides further comprises apartial-length-optical-core cladding, at least partially covering thepartial-length optical core; the partial-length-optical-core claddingcomprises at least a first partial-length-optical-core cladding resin,having a partial-length-optical-core first-cladding-resin refractiveindex; the partial-length-optical-core cladding is non-uniform alongeach of the partial-length optical waveguides; and thepartial-length-optical-core refractive index is greater than thepartial-length-optical-core first-cladding-resin refractive index. 39.The system according to claim 38, wherein: the partial-length peripheralsurface of the partial-length optical core of each of the partial-lengthoptical waveguides has partial-length-peripheral-surface regions devoidof the first partial-length-optical-core cladding resin; thepartial-length-optical-core cladding further comprises a secondpartial-length-optical-core cladding resin, having apartial-length-optical-core second-cladding-resin refractive index; thesecond partial-length-optical-core cladding resin covers thepartial-length-peripheral-surface regions of the partial-lengthperipheral surface; and the partial-length-optical-coresecond-cladding-resin refractive index is greater than thepartial-length-optical-core first-cladding-resin refractive index. 40.The system according to claim 39, wherein the secondpartial-length-optical-core cladding resin also covers the firstpartial-length-optical-core cladding resin.
 41. The system according toclaim 39, wherein: the resin has a resin refractive index; and the resinrefractive index is greater than the partial-length-optical-coresecond-cladding-resin refractive index.
 42. The system according toclaim 37, wherein the partial-length peripheral surface of thepartial-length optical core of each of the partial-length opticalwaveguides has a surface roughness that is selected such that whenelectromagnetic radiation enters the partial-length optical core via atleast one of the first partial-length-optical-core end face, the secondpartial-length-optical-core end face, or the partial-length peripheralsurface, at least a portion of the electromagnetic radiation exits thepartial-length optical core via the partial-length peripheral surface.43. The system according to claim 42, wherein each of the partial-lengthoptical waveguides is devoid of any cladding that covers thepartial-length optical core.
 44. The system according to claim 35,wherein: the optical direction modifiers comprise opticaldirection-modifying particles; and the optical direction-modifyingparticles are configured to at least one of reflect, refract, diffract,or Rayleigh-scatter the electromagnetic radiation, incident on the outersurface of any one of the optical direction-modifying particles todisperse the electromagnetic radiation.
 45. The system according toclaim 44, wherein: each of the elongate filaments has a minimum outerdimension; and each of the optical direction-modifying particles has amaximum outer dimension that is less than one-eighth the minimum outerdimension of any one of the elongate filaments.
 46. The system accordingto claim 44, wherein each of the optical direction-modifying particleshas a maximum outer dimension that is less than 1000 nm.
 47. The systemaccording to claim 44, wherein: the electromagnetic radiation has awavelength; and each of the optical direction-modifying particles has aminimum outer dimension that is greater than one-fourth the wavelengthof the electromagnetic radiation.
 48. The system according to claim 44,wherein each of the optical direction-modifying particles has a minimumouter dimension that is greater than or equal to 50 nm.
 49. The systemaccording to claim 44, wherein in the feedstock line, the opticaldirection-modifying particles comprise less than 10% by weight of theresin.
 50. The system according to claim 44, wherein the outer surfacesof at least some of the optical direction-modifying particles arefaceted.
 51. The system according to claim 44, wherein the outersurfaces of at least some of the optical direction-modifying particleshave a surface roughness that is selected such that when electromagneticradiation strikes the outer surfaces, the electromagnetic radiation isscattered.
 52. The system according to claim 44, wherein: the resin hasa resin refractive index; at least some of the opticaldirection-modifying particles have a particle refractive index; and theparticle refractive index is greater than or less than the resinrefractive index.
 53. (canceled)
 54. The system according to claim 44,wherein at least some of the optical direction-modifying particles areprismatic. 55-68. (canceled)
 69. A method of creating a feedstock linefor additive manufacturing of an object, the feedstock line having afeedstock-line length, the method comprising steps of: separating aprecursor prepreg tow, comprising elongate filaments and resin, coveringthe elongate filaments, into individual ones of the elongate filaments,at least partially covered with the resin, or into subsets of theelongate filaments, at least partially covered with the resin, whereineach of the subsets comprises a plurality of the elongate filaments;applying optical direction modifiers to the individual ones of theelongate filaments, at least partially covered with the resin, or to thesubsets of the elongate filaments, at least partially covered with theresin, wherein each of the optical direction modifiers has an outersurface, and wherein each of the optical direction modifiers isconfigured such that when electromagnetic radiation strikes the outersurface from a first direction, at least a portion of theelectromagnetic radiation departs the outer surface in a seconddirection that is at an angle to the first direction; combining theoptical direction modifiers with the individual ones of the elongatefilaments, at least partially covered with the resin, or the subsets ofthe elongate filaments, at least partially covered with the resin, intoa derivative prepreg tow so that the optical direction modifiers areinterspersed among the elongate filaments; and heating at least one of:the resin in the precursor prepreg tow prior to separating the precursorprepreg tow into the individual ones of the elongate filaments, at leastpartially covered with the resin, or into the subsets of the elongatefilaments, at least partially covered with the resin, to a firstthreshold temperature to facilitate separating the precursor prepregtow; the resin, at least partially covering the individual ones of theelongate filaments or the subsets of the elongate filaments followingseparating the precursor prepreg tow into the individual ones of theelongate filaments, at least partially covered with the resin, or intothe subsets of the elongate filaments, at least partially covered withthe resin, and prior to combining the optical direction modifiers andthe individual ones of the elongate filaments, at least partiallycovered with the resin, or the subsets of the elongate filaments, atleast partially covered with the resin, to a second thresholdtemperature to cause wet-out of the optical direction modifiers and theelongate filaments in the derivative prepreg tow by the resin; or theresin, at least partially covering the elongate filaments in thederivative prepreg tow, to a third threshold temperature to causewet-out of the optical direction modifiers and the elongate filaments inthe derivative prepreg tow by the resin. 70-119. (canceled)